#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define pb push_back
#define eb emplace_back
#define rz resize
#define Siz(a) (int)(a.size())
#define MP make_pair
#define MT make_tuple
#define IT iterator
#define fi first
#define se second
#define For(i, a, b) for (int i = (int)(a); i <= (int)(b); ++i)
#define Rep(i, a, b) for (int i = (int)(a); i >= (int)(b); --i)
#define CLR(a, v) memset(a, v, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(a))
#define debug cerr << "ztxakking\n"
#define y0 ztxaknoi
#define y1 ztxakioi
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using i128 = __int128_t;
using u128 = __uint128_t;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pil = pair<int, ll>;
using vi = vector<int>;
template<typename T>
using V = vector<T>;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
template<const int MOD>
struct Modular {
  int val;
  Modular(int x = 0) : val(x) {}
  friend Modular operator + (Modular x, Modular y) { int res = x.val + y.val; if (res >= MOD) res -= MOD; return res; }
  friend Modular operator - (Modular x, Modular y) { int res = x.val - y.val; if (res < 0) res += MOD; return res; }
  friend Modular operator * (Modular x, Modular y) { int res = 1ll * x.val * y.val % MOD; return res; }
  Modular &operator += (Modular x) { *this = *this + x; return *this; }
  Modular &operator -= (Modular x) { *this = *this - x; return *this; }
  Modular &operator *= (Modular x) { *this = *this * x; return *this; }
  Modular &operator ++ () { *this = *this + 1; return *this; }
  Modular &operator ++ (int) { *this = *this + 1; return *this; }
  Modular &operator -- () { *this = *this - 1; return *this; }
  Modular &operator -- (int) { *this = *this - 1; return *this; }
  Modular operator - () { int res = val; if (res) res = MOD - res; return res; }
  static Modular pow(Modular x, ll p) {
    Modular ans(1);
    for (; p; p /= 2, x *= x) {
      if (p & 1) ans *= x;
    }
    return ans;
  }
  static Modular inv(Modular x) { return pow(x, MOD - 2); }
  friend Modular operator / (Modular x, Modular y) { return x * inv(y); }
  Modular &operator /= (Modular x) { *this = *this / x; return *this; }
  friend bool operator == (Modular x, Modular y) { return x.val == y.val; }
  friend bool operator != (Modular x, Modular y) { return x.val != y.val; }
  friend bool operator < (Modular x, Modular y) { return x.val < y.val; }
  friend bool operator > (Modular x, Modular y) { return x.val > y.val; }
  friend bool operator <= (Modular x, Modular y) { return x.val <= y.val; }
  friend bool operator >= (Modular x, Modular y) { return x.val >= y.val; }
  friend istream &operator >> (istream &in, Modular &item) { in >> item.val; return in; }
  friend ostream &operator << (ostream &out, Modular item) { out << item.val; return out; }
};
using mint = Modular<998244353>;
const int N = 1e5 + 7;
int n, dep[N];
vi G[N];
V<mint> f[N], g;
mint fac[N], ifac[N];
void dfs(int u, int fa) {
  dep[u] = dep[fa] + 1, f[u].rz(dep[u] + 1, 0), f[u][0] = 1;
  for (int v : G[u]) {
    dfs(v, u);
    g.assign(dep[u] + 1, 0);
    For(i, 0, dep[u]) For(j, 0, min(dep[u] - i, dep[v])) g[i + j] += f[u][i] * f[v][j];
    f[u].swap(g);
  }
  g.assign(dep[u], 0);
  For(i, 0, dep[u]) For(j, 0, dep[u] - i) {
    if (i + j > 0) g[i + j - 1] += f[u][i] * ifac[j];
  }
  f[u].swap(g);
}
void Main() {
  cin >> n;
  fac[0] = 1;
  For(i, 1, n) fac[i] = fac[i - 1] * i;
  ifac[n] = 1 / fac[n];
  Rep(i, n, 1) ifac[i - 1] = ifac[i] * i;
  For(i, 2, n) {
    int p; cin >> p, G[p].pb(i);
  }
  For(i, 1, n) f[i].clear();
  dfs(1, 0);
  cout << f[1][0] * fac[n] << '\n';
}
int main() {
  #ifndef ONLINE_JUDGE
  freopen("A.in", "r", stdin) && freopen("A.out", "w", stdout);
  #endif
  ios::sync_with_stdio(0), cin.tie(0);
  int t = 1;
  // cin >> t;
  while (t--) Main();
  cerr << (double)(clock()) / CLOCKS_PER_SEC << '\n';
  return 0;
}