#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
int main(){
  int N;
  cin >> N;
  string S;
  cin >> S;
  reverse(S.begin(), S.end());
  for (int i = 0; i < N; i++){
    S += '0';
  }
  vector<long long> POW(N);
  POW[0] = 1;
  for (int i = 0; i < N - 1; i++){
    POW[i + 1] = POW[i] * 2 % MOD;
  }
  long long ans = 0;
  for (int i = 0; i < N; i++){
    vector<long long> dp(N + 1, 0);
    dp[0] = 1;
    vector<long long> imos(N + 2, 0);
    for (int j = 0; j < N; j++){
      dp[j] += imos[j];
      dp[j] %= MOD;
      imos[j + 1] += imos[j];
      imos[j + 1] %= MOD;
      if (S[j + i] == '0'){
        imos[j + 1] += dp[j];
        imos[j + 1] %= MOD;
        imos[N + 1] += MOD - dp[j];
        imos[N + 1] %= MOD;
      } else {
        imos[j + 1] += dp[j];
        imos[j + 1] %= MOD;
        imos[min(N, j + i) + 1] += MOD - dp[j];
        imos[min(N, j + i) + 1] %= MOD;
      }
    }
    dp[N] += imos[N];
    dp[N] %= MOD;
    ans += POW[i] * (POW[N - 1] - dp[N] + MOD) % MOD;
  }
  ans %= MOD;
  cout << ans << endl;
}