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

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

    int N; cin >> N;
    string s; cin >> s;
    vector dp(N+1,vector<long long>(2));
    dp.at(0).at(0) = 1;
    long long mod = 998244353;
    for(int i=0; i<N; i++) for(int k=0; k<2; k++){
        if(k == 1) dp.at(i+1).at(1) = (dp.at(i+1).at(1)+dp.at(i).at(k))%mod;

        if(s.at(i) == '1') dp.at(i+1).at(1) = (dp.at(i+1).at(1)+dp.at(i).at(k))%mod;
        else dp.at(i+1).at(0) = (dp.at(i+1).at(0)+dp.at(i).at(k))%mod;
    }    
    cout << dp.at(N).at(1) << endl;
}