#include<algorithm>
#include<iostream>
#include<vector>
#include<map>
#include<cassert>
#include<set>
#include<queue>
#include<cstdint>
#include<unordered_map>
using namespace std;
using ll = long long;
#include<stack>


#include<atcoder/modint>
using mint = atcoder::modint998244353;

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

    int n;
    cin>>n;
    string s;
    cin>>s;
    vector<mint> sum(n+1,0);
    vector<mint> dp(n+1,0);
    dp[0] = 1;
    int last = -1;
    for(int i = 0;i<n;i++){
        if(s[i]=='1') last = i;
        sum[i+1] += dp[i] + sum[i];
        if(last==-1) continue;
        mint tmp = sum[last+1];
        //cout<<tmp.val()<<endl;
        dp[i+1] += tmp;
    }
    cout<<dp[n].val()<<endl;
}