#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(void) {
  ll N;
  string A;
  cin >> N >> A;
  A += '0';
  ll l = 0;
  while (l < N && A[l] == '1')
    l++;

  ll ans = 1;
  ll len = 0;
  char b = '0';
  for (int i = l; i <= N; i++) {
    if (b == '1' && A[i] == '0') {
      ans *= (len + 1);
      ans %= 998244353;
      len = 0;
    }
    len++;
    b = A[i];
  }

  cout << ans << endl;

  return (0);
}