#include<bits/stdc++.h>
using namespace std;
const int mod=998244353;
int main(){
  int n;
  cin>>n;
  string s;
  cin>>s;
  s=" "+s;
  vector<vector<long long>> dp(n+2,vector<long long> (n+2));
  vector<vector<long long>> sum(n+2,vector<long long> (n+2));
  dp[0][n]=1;
    for (int i=1; i<=n; i++) {
        sum[0][i]=1;
    }
    for (int i=1; i<=n; i++) {
        for (int j=0; j<=n; j++) {
            if (s[i]=='0') {
                dp[i][j]=(dp[i-1][j]*(n-i-j+1)+sum[i-1][j+1])%mod;
            } else {
                dp[i][j]=(j+1)*dp[i-1][j+1]%mod;
            }
        }
        for (int j=n; j; j--) {
            sum[i][j]=(sum[i][j+1]+dp[i][j])%mod;
        }
    }
    cout << dp[n][0];
  return 0;
}