#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using uns= unsigned long long;
#define rep(i,a,b) for(ll i = (a); i < (b); i++)

int main() {
    int N;
    cin>>N;
    string S;
    cin>>S;
    ll answer=1;
    int m=998244353;
    int x=0;
    int ok=0;
    if(S.at(0)=='0'){
        x=1;
        ok=1;
    }
    rep(i,0,N-1){
        x++;
        if(S.at(i)=='1'&&S.at(i+1)=='0'){
            if(ok){
                answer*=x;
                answer%=m;

            }
            ok=1;
            x=1;
        }
    }
    x++;
    if(S.at(N-1)=='1'&&ok){
        answer*=x;
        answer%=m;
    }
    cout<<answer<<endl;



}