#include <bits/stdc++.h>
#include <iostream>
#include <cmath>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    int N;
    string A;
    cin >> N >> A;
    int md = -1;
    long long p = 1LL, ren = 0LL, div = 998244353;
    rep (i, N) {
        if (md == -1 && A[i] == '0') {
            md = 0;
        }
        if (md == 1 && A[i] == '0') {
            md = 0;
            ren++;
            p *= ren;
            p %= div;
            ren = 0LL;
        }
        if (md == 0 && A[i] == '1') {
            md = 1;
        }
        ren++;
    }
    if (md == 1) {
        ren++;
        p *= ren;
        p %= div;
    }
    cout << p << endl;
}