#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;

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

    vector<int> left_one(N + 1, 1), right_zero(N + 1, 1);
    for (int i = 0; i < N; i++) {
        if (A[i] == '0') left_one[i + 1] = 0;
        left_one[i + 1] &= left_one[i];
    }
    for (int i = N - 1; i >= 0; i--) {
        if (A[i] == '1') right_zero[i] = 0;
        right_zero[i] &= right_zero[i + 1];
    }

    long long ans = 0;
    for (int i = 0; i <= N; i++) {
        if (left_one[i] && right_zero[i]) ans++;
    }
    cout << ans % MOD << endl;
}