#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

namespace {

using Fp = atcoder::modint998244353;

Comb<Fp> comb(1000);

void solve() {
  int n;
  scan(n);
  vector<int> a(n);
  scan(a);

  vector<Fp> f{1};
  for (int e : a | views::reverse) {
    vector<Fp> nf(len(f) + e);
    for (int k : rep(len(f))) {
      // [0, k] に e 個挿入する
      for (int c0 : rep(e + 1)) {
        // 0 に c0 個挿入する
        if (c0 < e) {
          for (int i : rep1(k)) {
            // (0, i) には挿入しない、i には 1 個以上挿入する
            // e-c0-1 個を [i, k] の k-i+1 箇所に分割する
            nf[c0 + i] += f[k] * comb.multiset(k - i + 1, e - c0 - 1);
          }
        } else {
          // 0 only
          nf[c0 + k] += f[k];
        }
      }
    }
    f = move(nf);
  }

  Fp ans = ALL(accumulate, f, Fp(0));
  print(ans);
}

}  // namespace

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  solve();
}

#else  // __INCLUDE_LEVEL__

#include <bits/stdc++.h>

using namespace std;

#define ALL(f, r, ...) [&](auto&& _) { return f(begin(_), end(_), ##__VA_ARGS__); }(r)

template <class T>
vector<T> make_vector_for_overwrite(int n) {
  static_assert(is_trivially_destructible_v<T>);
  vector<T> v;
  v.reserve(n);
  auto p = (T**)&v;
  p[1] = p[2];
  return v;
}

template <class T>
class Comb {
 public:
  Comb() = default;

  explicit Comb(int max_n)
      : fact_(make_vector_for_overwrite<T>(max_n + 1)),
        recip_fact_(make_vector_for_overwrite<T>(max_n + 1)) {
    fact_[0] = 1;
    for (int n = 1; n <= max_n; ++n) {
      fact_[n] = fact_[n - 1] * n;
    }
    recip_fact_[max_n] = 1 / fact_[max_n];
    for (int n = max_n; 1 <= n; --n) {
      recip_fact_[n - 1] = n * recip_fact_[n];
    }
  }

  T recip(int n) const {
    assert(n);
    return n < 0 ? -recip(-n) : recip_fact_[n] * fact_[n - 1];
  }

  T fact(int n) const {
    assert(0 <= n);
    return fact_[n];
  }

  T recip_fact(int n) const { return n < 0 ? 0 : recip_fact_[n]; }

  T falling_fact(int n, int k) const {
    assert(0 <= n || n < k);
    if (n < 0) {
      T t = falling_fact(k - n - 1, k);
      return k & 1 ? -t : t;
    }
    return n < k ? 0 : recip_fact(n - k) * fact(n);
  }

  T recip_falling_fact(int n, int k) const {
    assert(n < 0 || k <= n);
    return falling_fact(n - k, -k);
  }

  T rising_fact(int n, int k) const {
    assert(n <= 0 || 0 < n + k);
    return falling_fact(n + k - 1, k);
  }

  T recip_rising_fact(int n, int k) const {
    assert(0 < n || n + k <= 0);
    return falling_fact(n - 1, -k);
  }

  T binom(int n, int k) const {
    if ((n < 0) ^ (k < 0) ^ (n < k)) {
      return 0;
    }
    if (n < 0 && k < 0) {
      k = n - k;
    }
    return recip_fact(k) * falling_fact(n, k);
  }

  T recip_binom(int n, int k) const {
    assert((0 <= n) ^ (0 <= k) ^ (k <= n));
    k = max(k, n - k);
    return recip_falling_fact(n, k) * fact(k);
  }

  T multiset(int n, int k) const { return binom(n + k - 1, k); }

  T recip_multiset(int n, int k) const {
    assert((0 < n) ^ (0 <= k) ^ (0 < n + k));
    return recip_binom(n + k - 1, k);
  }

 private:
  vector<T> fact_;
  vector<T> recip_fact_;
};

namespace atcoder {

namespace internal {

constexpr long long safe_mod(long long x, long long m) {
  x %= m;
  if (x < 0) x += m;
  return x;
}

struct barrett {
  unsigned int _m;
  unsigned long long im;

  explicit barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}

  unsigned int umod() const { return _m; }

  unsigned int mul(unsigned int a, unsigned int b) const {
    unsigned long long z = a;
    z *= b;
    unsigned long long x = (unsigned long long)(((unsigned __int128)(z)*im) >> 64);
    unsigned long long y = x * _m;
    return (unsigned int)(z - y + (z < y ? _m : 0));
  }
};

constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
  if (m == 1) return 0;
  unsigned int _m = (unsigned int)(m);
  unsigned long long r = 1;
  unsigned long long y = safe_mod(x, m);
  while (n) {
    if (n & 1) r = (r * y) % _m;
    y = (y * y) % _m;
    n >>= 1;
  }
  return r;
}

constexpr bool is_prime_constexpr(int n) {
  if (n <= 1) return false;
  if (n == 2 || n == 7 || n == 61) return true;
  if (n % 2 == 0) return false;
  long long d = n - 1;
  while (d % 2 == 0) d /= 2;
  constexpr long long bases[3] = {2, 7, 61};
  for (long long a : bases) {
    long long t = d;
    long long y = pow_mod_constexpr(a, t, n);
    while (t != n - 1 && y != 1 && y != n - 1) {
      y = y * y % n;
      t <<= 1;
    }
    if (y != n - 1 && t % 2 == 0) {
      return false;
    }
  }
  return true;
}
template <int n>
constexpr bool is_prime = is_prime_constexpr(n);

constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
  a = safe_mod(a, b);
  if (a == 0) return {b, 0};

  long long s = b, t = a;
  long long m0 = 0, m1 = 1;

  while (t) {
    long long u = s / t;
    s -= t * u;
    m0 -= m1 * u;

    auto tmp = s;
    s = t;
    t = tmp;
    tmp = m0;
    m0 = m1;
    m1 = tmp;
  }
  if (m0 < 0) m0 += b / s;
  return {s, m0};
}

constexpr int primitive_root_constexpr(int m) {
  if (m == 2) return 1;
  if (m == 167772161) return 3;
  if (m == 469762049) return 3;
  if (m == 754974721) return 11;
  if (m == 998244353) return 3;
  int divs[20] = {};
  divs[0] = 2;
  int cnt = 1;
  int x = (m - 1) / 2;
  while (x % 2 == 0) x /= 2;
  for (int i = 3; (long long)(i)*i <= x; i += 2) {
    if (x % i == 0) {
      divs[cnt++] = i;
      while (x % i == 0) {
        x /= i;
      }
    }
  }
  if (x > 1) {
    divs[cnt++] = x;
  }
  for (int g = 2;; g++) {
    bool ok = true;
    for (int i = 0; i < cnt; i++) {
      if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) {
        ok = false;
        break;
      }
    }
    if (ok) return g;
  }
}
template <int m>
constexpr int primitive_root = primitive_root_constexpr(m);

unsigned long long floor_sum_unsigned(unsigned long long n, unsigned long long m,
                                      unsigned long long a, unsigned long long b) {
  unsigned long long ans = 0;
  while (true) {
    if (a >= m) {
      ans += n * (n - 1) / 2 * (a / m);
      a %= m;
    }
    if (b >= m) {
      ans += n * (b / m);
      b %= m;
    }

    unsigned long long y_max = a * n + b;
    if (y_max < m) break;
    n = (unsigned long long)(y_max / m);
    b = (unsigned long long)(y_max % m);
    std::swap(m, a);
  }
  return ans;
}

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

namespace internal {

template <class T>
using is_signed_int128 = typename std::conditional<std::is_same<T, __int128_t>::value ||
                                                       std::is_same<T, __int128>::value,
                                                   std::true_type, std::false_type>::type;

template <class T>
using is_unsigned_int128 = typename std::conditional<std::is_same<T, __uint128_t>::value ||
                                                         std::is_same<T, unsigned __int128>::value,
                                                     std::true_type, std::false_type>::type;

template <class T>
using make_unsigned_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value, __uint128_t, unsigned __int128>;

template <class T>
using is_integral =
    typename std::conditional<std::is_integral<T>::value || is_signed_int128<T>::value ||
                                  is_unsigned_int128<T>::value,
                              std::true_type, std::false_type>::type;

template <class T>
using is_signed_int =
    typename std::conditional<(is_integral<T>::value && std::is_signed<T>::value) ||
                                  is_signed_int128<T>::value,
                              std::true_type, std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<(is_integral<T>::value && std::is_unsigned<T>::value) ||
                                  is_unsigned_int128<T>::value,
                              std::true_type, std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<
    is_signed_int128<T>::value, make_unsigned_int128<T>,
    typename std::conditional<std::is_signed<T>::value, std::make_unsigned<T>,
                              std::common_type<T>>::type>::type;

template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

template <class T>
using to_unsigned_t = typename to_unsigned<T>::type;

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

namespace internal {

struct modint_base {};
struct static_modint_base : modint_base {};

template <class T>
using is_modint = std::is_base_of<modint_base, T>;
template <class T>
using is_modint_t = std::enable_if_t<is_modint<T>::value>;

}  // namespace internal

template <int m, std::enable_if_t<(1 <= m)>* = nullptr>
struct static_modint : internal::static_modint_base {
  using mint = static_modint;

 public:
  static constexpr int mod() { return m; }
  static mint raw(int v) {
    mint x;
    x._v = v;
    return x;
  }

  static_modint() : _v(0) {}
  template <class T, internal::is_signed_int_t<T>* = nullptr>
  static_modint(T v) {
    long long x = (long long)(v % (long long)(umod()));
    if (x < 0) x += umod();
    _v = (unsigned int)(x);
  }
  template <class T, internal::is_unsigned_int_t<T>* = nullptr>
  static_modint(T v) {
    _v = (unsigned int)(v % umod());
  }

  unsigned int val() const { return _v; }

  mint& operator++() {
    _v++;
    if (_v == umod()) _v = 0;
    return *this;
  }
  mint& operator--() {
    if (_v == 0) _v = umod();
    _v--;
    return *this;
  }
  mint operator++(int) {
    mint result = *this;
    ++*this;
    return result;
  }
  mint operator--(int) {
    mint result = *this;
    --*this;
    return result;
  }

  mint& operator+=(const mint& rhs) {
    _v += rhs._v;
    if (_v >= umod()) _v -= umod();
    return *this;
  }
  mint& operator-=(const mint& rhs) {
    _v -= rhs._v;
    if (_v >= umod()) _v += umod();
    return *this;
  }
  mint& operator*=(const mint& rhs) {
    unsigned long long z = _v;
    z *= rhs._v;
    _v = (unsigned int)(z % umod());
    return *this;
  }
  mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

  mint operator+() const { return *this; }
  mint operator-() const { return mint() - *this; }

  mint pow(long long n) const {
    assert(0 <= n);
    mint x = *this, r = 1;
    while (n) {
      if (n & 1) r *= x;
      x *= x;
      n >>= 1;
    }
    return r;
  }
  mint inv() const {
    if (prime) {
      assert(_v);
      return pow(umod() - 2);
    } else {
      auto eg = internal::inv_gcd(_v, m);
      assert(eg.first == 1);
      return eg.second;
    }
  }

  friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; }
  friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; }
  friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; }
  friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; }
  friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; }
  friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; }

 private:
  unsigned int _v;
  static constexpr unsigned int umod() { return m; }
  static constexpr bool prime = internal::is_prime<m>;
};

template <int id>
struct dynamic_modint : internal::modint_base {
  using mint = dynamic_modint;

 public:
  static int mod() { return (int)(bt.umod()); }
  static void set_mod(int m) {
    assert(1 <= m);
    bt = internal::barrett(m);
  }
  static mint raw(int v) {
    mint x;
    x._v = v;
    return x;
  }

  dynamic_modint() : _v(0) {}
  template <class T, internal::is_signed_int_t<T>* = nullptr>
  dynamic_modint(T v) {
    long long x = (long long)(v % (long long)(mod()));
    if (x < 0) x += mod();
    _v = (unsigned int)(x);
  }
  template <class T, internal::is_unsigned_int_t<T>* = nullptr>
  dynamic_modint(T v) {
    _v = (unsigned int)(v % mod());
  }

  unsigned int val() const { return _v; }

  mint& operator++() {
    _v++;
    if (_v == umod()) _v = 0;
    return *this;
  }
  mint& operator--() {
    if (_v == 0) _v = umod();
    _v--;
    return *this;
  }
  mint operator++(int) {
    mint result = *this;
    ++*this;
    return result;
  }
  mint operator--(int) {
    mint result = *this;
    --*this;
    return result;
  }

  mint& operator+=(const mint& rhs) {
    _v += rhs._v;
    if (_v >= umod()) _v -= umod();
    return *this;
  }
  mint& operator-=(const mint& rhs) {
    _v += mod() - rhs._v;
    if (_v >= umod()) _v -= umod();
    return *this;
  }
  mint& operator*=(const mint& rhs) {
    _v = bt.mul(_v, rhs._v);
    return *this;
  }
  mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

  mint operator+() const { return *this; }
  mint operator-() const { return mint() - *this; }

  mint pow(long long n) const {
    assert(0 <= n);
    mint x = *this, r = 1;
    while (n) {
      if (n & 1) r *= x;
      x *= x;
      n >>= 1;
    }
    return r;
  }
  mint inv() const {
    auto eg = internal::inv_gcd(_v, mod());
    assert(eg.first == 1);
    return eg.second;
  }

  friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; }
  friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; }
  friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; }
  friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; }
  friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; }
  friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; }

 private:
  unsigned int _v;
  static internal::barrett bt;
  static unsigned int umod() { return bt.umod(); }
};
template <int id>
internal::barrett dynamic_modint<id>::bt(998244353);

using modint998244353 = static_modint<998244353>;
using modint1000000007 = static_modint<1000000007>;
using modint = dynamic_modint<-1>;

namespace internal {

template <class T>
using is_static_modint = std::is_base_of<internal::static_modint_base, T>;

template <class T>
using is_static_modint_t = std::enable_if_t<is_static_modint<T>::value>;

template <class>
struct is_dynamic_modint : public std::false_type {};
template <int id>
struct is_dynamic_modint<dynamic_modint<id>> : public std::true_type {};

template <class T>
using is_dynamic_modint_t = std::enable_if_t<is_dynamic_modint<T>::value>;

}  // namespace internal

}  // namespace atcoder

template <class T>
concept tuple_like = __is_tuple_like<T>::value && !ranges::range<T>;

template <class R>
concept nstr_range = ranges::range<R> && !convertible_to<R, string_view>;

namespace std {

istream& operator>>(istream& is, tuple_like auto&& t) {
  return apply([&is](auto&... xs) -> istream& { return (is >> ... >> xs); }, t);
}

istream& operator>>(istream& is, nstr_range auto&& r) {
  for (auto&& e : r) {
    is >> e;
  }
  return is;
}

ostream& operator<<(ostream& os, tuple_like auto&& t) {
  auto f = [&os](auto&... xs) -> ostream& {
    [[maybe_unused]] auto sep = "";
    ((os << exchange(sep, " ") << xs), ...);
    return os;
  };
  return apply(f, t);
}

ostream& operator<<(ostream& os, nstr_range auto&& r) {
  auto sep = "";
  for (auto&& e : r) {
    os << exchange(sep, " ") << e;
  }
  return os;
}

#define DEF_INC_OR_DEC(op) \
  auto& operator op(tuple_like auto&& t) { \
    apply([](auto&... xs) { (op xs, ...); }, t); \
    return t; \
  } \
  auto& operator op(nstr_range auto&& r) { \
    for (auto&& e : r) { \
      op e; \
    } \
    return r; \
  }

DEF_INC_OR_DEC(++)
DEF_INC_OR_DEC(--)

#undef DEF_INC_OR_DEC

}  // namespace std

namespace atcoder {

template <class T, internal::is_modint_t<T>* = nullptr>
istream& operator>>(istream& is, T& x) {
  int v;
  is >> v;
  x = T::raw(v);
  return is;
}

template <class T, internal::is_modint_t<T>* = nullptr>
ostream& operator<<(ostream& os, const T& x) {
  return os << x.val();
}

}  // namespace atcoder

void scan(auto&&... xs) { cin >> tie(xs...); }
void print(auto&&... xs) { cout << tie(xs...) << '\n'; }

using views::drop;
using views::take;
inline constexpr auto rev = views::reverse;
inline constexpr auto len = ranges::ssize;
inline auto rep(int l, int r) { return views::iota(min(l, r), r); }
inline auto rep(int n) { return rep(0, n); }
inline auto rep1(int l, int r) { return rep(l, r + 1); }
inline auto rep1(int n) { return rep(1, n + 1); }

#endif  // __INCLUDE_LEVEL__