/* -*- coding: utf-8 -*-
 *
 * 3500.cc:  No.3500 01 String - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 500000;
const int MOD = 998244353;

/* typedef */

using ll = long long;

/* global variables */

char s[MAX_N + 8];
int cs[MAX_N + 1];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d%s", &n, s + 1);

  s[0] = '1', s[n + 1] = '0';
  int k = 0;
  for (int i = 0; i <= n; i++)
    if (s[i] == '1' && s[i + 1] == '0') cs[k++] = i;

  ll p = 1;
  for (int i = 0; i + 1 < k; i++)
    p = p * (cs[i + 1] - cs[i] + 1) % MOD;

  printf("%lld\n", p);
  
  return 0;
}