#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
//using mint = modint998244353;
int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    ll n;
    string a;
    cin >> n >> a;
    a += '2';
    vector<ll> z(0);
    ll count = 1;
    for(ll i = 0; i < n; i++){
        if(a[i] != a[i+1]){
            if(z.size() > 0 || a[i] == '0'){
                z.push_back(count);
            }
            count = 1;
        }else{
            count++;
        }
    }

    ll ans = 1;
    if(z.size() > 1){
        for(ll i = 0; i < z.size()-1; i += 2){
            ans *= z[i] + z[i+1] + 1;
            ans %= 998244353;
        }
    }
    

    cout << ans << '\n';

}