#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
const i64 INF = 1001001001001001001;

using Modint = atcoder::static_modint<998244353>;

int main(){
    int N; cin >> N;
    string S; cin >> S;
    Modint p2 = 1;
    Modint allc = Modint(2).pow(N-1);
    Modint ans = 0;
    for(int d=1; d<=N; d++){
        std::vector<Modint> X(N+1);
        std::vector<Modint> Xsum(N+2);
        X[0] = 1;
        for(int k=1; k<=N; k++){
            Xsum[k] = Xsum[k-1] + X[k-1];
            if(k >= d && S[k-d] == '1'){
                X[k] = Xsum[k] - Xsum[k-d+1];
            }
            else{
                X[k] = Xsum[k];
            }
        }
        ans += (allc - X[N]) * p2;
        p2 += p2;
    }
    cout << ans.val() << endl;
    return 0;
}



struct ios_do_not_sync{
    ios_do_not_sync(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;