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

long long MOD = 998244353;

int main() {
    int N;
    string A;
    cin >> N >> A;

    string B;
    B.push_back('1');
    B += A;
    B.push_back('0');

    vector<int> C;
    for (int i = 1; i < B.size(); ++i) {
        if (B[i - 1] == '1' && B[i] == '0') {
            C.push_back(i);
        }
    }

    long long ans = 1;
    for (int i = 1; i < C.size(); ++i) {
        ans = ans * (C[i] - C[i - 1] + 1) % MOD;
    }

    cout << ans << endl;
}