#include <bits/stdc++.h>
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define st first
#define nd second
using namespace std;
typedef long long ll;
const int mod = 998244353;
const int N = 1e6 + 5;

string str;
struct eertree {
  int cnt = 2, suf = 1;
  vector<int> lnk, len, vis;
  vector<array<int,10>> go;
  eertree(int n) : lnk(n+3), len(n+3), go(n+3), vis(n+3) {
    len[1] = -1, len[2] = 0;
    lnk[1] = 1, lnk[2] = 1;
  }
  int walk(int i, int v) {
    while (i-1-len[v] < 0 || str[i-1-len[v]] != str[i])
      v = lnk[v];
    return v;
  }
  void add(int i, int m, int j) {
    int c = str[i]-'0', lst = walk(i, suf);
    if (!go[lst][c]) {
      go[lst][c] = ++cnt;
      len[cnt] = len[lst] + 2;
      lnk[cnt] = lst > 1 ? go[walk(i,lnk[lst])][c] : 2;
    }
    suf = go[lst][c];
    vis[suf]++;
    if (i >= m)
      vis[j]--;
  }
};

int main() {
  ios_base::sync_with_stdio(false); cin.tie(0);
  int n; cin >> n;
  cin >> str;
  str += str;
  eertree e(2 * n);
  int ans = 0;
  vector<int> bad(n);
  for (int i = 0; i < 2 * n; i++) {
    e.add(i, n, i >= n ? bad[i - n] : 0);
    if (i < n)
    	bad[i] = e.suf;
  }
  for (int i = e.cnt; i > 2; i--) {
    e.vis[e.lnk[i]] += e.vis[i];
    if (e.len[i] <= n)
      ans = (ans + (e.vis[i] * 1ll * e.vis[i]) % mod * 1ll * e.len[i]) % mod;
  }
  cout << ans << "\n";
}