#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int N;
  cin >> N;
  string A;
  cin >> A;
  int count = 0;
  int ans = 1;
  bool flag = false;
  char ibit;
  for(int i = 0; i < N; i++){
    ibit = A.at(i);
    if(!flag){
      if(ibit == '0'){
        flag = true;
        count++;
      }
    }
    else{
      if(A.at(i) == '0' && A.at(i-1) == '1'){
        ans *= count+1;
        ans = ans % 998244353;
        count = 1;
      }
      else{
        count++;
      }
    }
    if(i == N-1){
      if(ibit == '1'){
        ans *= count+1;
        ans = ans % 998244353;
      }
    }
  }
  cout << ans << endl;
  return 0;
}