#pragma GCC optimize(2, 3, "Ofast", "unroll-loops")
#include <bits/stdc++.h>
#ifdef dbg
#define D(...) fprintf(stderr, __VA_ARGS__)
#define DD(...) D(#__VA_ARGS__ " = "), debug_helper::debug(__VA_ARGS__), D("\n")
#include "C:\Users\wsyear\Desktop\OI\templates\debug.hpp"
#else
#define D(...) ((void)0)
#define DD(...) ((void)0)
#endif
#define rep(i, j, k) for (int i = (j); i <= (k); ++i)
#define per(i, j, k) for (int i = (j); i >= (k); --i)
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;

using namespace std;

template <int P>
class mod_int {
  using Z = mod_int;

private:
  static int mo(int x) { return x < 0 ? x + P : x; }

public:
  int x;
  int val() const { return x; }
  mod_int() : x(0) {}
  template <class T>
  mod_int(const T &x_) : x(x_ >= 0 && x_ < P ? static_cast<int>(x_) : mo(static_cast<int>(x_ % P))) {}
  bool operator==(const Z &rhs) const { return x == rhs.x; }
  bool operator!=(const Z &rhs) const { return x != rhs.x; }
  Z operator-() const { return Z(x ? P - x : 0); }
  Z pow(long long k) const {
    Z res = 1, t = *this;
    while (k) {
      if (k & 1) res *= t;
      if (k >>= 1) t *= t;
    }
    return res;
  }
  Z &operator++() {
    x < P - 1 ? ++x : x = 0;
    return *this;
  }
  Z &operator--() {
    x ? --x : x = P - 1;
    return *this;
  }
  Z operator++(int) {
    Z ret = x;
    x < P - 1 ? ++x : x = 0;
    return ret;
  }
  Z operator--(int) {
    Z ret = x;
    x ? --x : x = P - 1;
    return ret;
  }
  Z inv() const { return pow(P - 2); }
  Z &operator+=(const Z &rhs) {
    (x += rhs.x) >= P && (x -= P);
    return *this;
  }
  Z &operator-=(const Z &rhs) {
    (x -= rhs.x) < 0 && (x += P);
    return *this;
  }
  Z &operator*=(const Z &rhs) {
    x = 1ULL * x * rhs.x % P;
    return *this;
  }
  Z &operator/=(const Z &rhs) { return *this *= rhs.inv(); }
#define setO(T, o)                                 \
  friend T operator o(const Z &lhs, const Z &rhs) {\
    Z res = lhs;                                   \
    return res o## = rhs;                          \
  }
  setO(Z, +) setO(Z, -) setO(Z, *) setO(Z, /)
#undef setO
};
const int P = 998244353;
using Z = mod_int<P>;

const int maxn = 6000010;

char s[maxn];
int n, len[maxn], num[maxn], fail[maxn];
Z cnt[maxn];
int cur = 1, pos = 1, trie[maxn][10], tot = 2, edp[maxn];
vector<int> e[maxn];

void mem() {
  cur = 1, pos = 1, tot = 2;
  rep (i, 0, maxn - 1) rep (j, 0, 9) trie[i][j] = 1;
  rep (i, 0, maxn - 1) fail[i] = 1, cnt[i] = 0;
}

int getfail(int x, int i) {
  while (i - len[x] - 1 < 0 || s[i - len[x] - 1] != s[i]) x = fail[x];
  return x;
}

void ins(char ch, int i) {
  pos = getfail(cur, i);
  if (trie[pos][ch - '0'] == 1) {
  	fail[++tot] = trie[getfail(fail[pos], i)][s[i] - '0'];
  	trie[pos][s[i] - '0'] = tot;
  	len[tot] = len[pos] + 2;
    num[tot] = num[fail[tot]] + 1;
  }
  cur = trie[pos][s[i] - '0'];
  edp[i + 1] = cur, cnt[cur]++;
}

void dfs(int u) {
  for (int v : e[u]) dfs(v), cnt[u] += cnt[v];
}

int main() {
  cin.tie(nullptr) -> ios::sync_with_stdio(false);
  cin >> n >> s;
  Z ans = 0;
  rep (i, n, 2 * n - 1) s[i] = s[i - n];
  mem();
  fail[1] = 2, fail[2] = 2;
  len[2] = -1, len[1] = 0;
  rep (i, 0, 2 * n - 1) ins(s[i], i);
  rep (i, 0, n - 1) cnt[edp[i + 1]]--;
  rep (i, 1, tot) if (fail[i] && i != 2) e[fail[i]].emplace_back(i);
  dfs(2);
  rep (i, 1, tot) if (len[i] >= 0 && len[i] <= n) ans += Z(len[i]) * cnt[i] * cnt[i];
  cout << ans.val() << '\n';
}