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

static const long long MOD = 998244353;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    string A;
    cin >> N >> A;

    vector<pair<char,int>> runs;
    for (char c : A) {
        if (runs.empty() || runs.back().first != c) {
            runs.push_back({c, 1});
        } else {
            runs.back().second++;
        }
    }

    long long ans = 1;
    for (int i = 0; i + 1 < (int)runs.size(); i++) {
        if (runs[i].first == '0' && runs[i + 1].first == '1') {
            ans = ans * (runs[i].second + runs[i + 1].second + 1) % MOD;
        }
    }

    cout << ans << '\n';
    return 0;
}