#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <math.h>
#include <cmath>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <iomanip>
#include <climits>
#include <functional>
#include <cassert>
#include <tuple>
using namespace std;
using ll = long long;

int N;
string S;
ll mod = 998244353;

int main() {

    cin >> N >> S;
    vector<ll> pos1;
    for(int i = 0; i < N; ++i) {
        if(S[i] == '1') pos1.push_back(i);
    }

    if(pos1.size() == 0) {
        cout << 0 << endl;
        return 0;
    }

    ll ans = 1;
    for(int i = 0; i < pos1.size()-1; ++i) {
        ans *= pos1[i+1]-pos1[i]+1;
        ans %= mod;
    }

    cout << ans << endl;

}