#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  string s;
  cin >> s;
  mint ans;
  rep(k, n) {
    vector<mint> dp(n + 1);
    dp[n] = 1;
    dp[n - 1] = -1;
    for(int i = n; i > 0; i--) {
      dp[i - 1] += dp[i];
      dp[i - 1] += dp[i];
      if (i - 1 - k >= 0 && s[i - 1 - k] == '1') {
        dp[i - 1 - k] -= dp[i];
      }
    }
    ans += (mint(2).pow(n - 1) - dp[0]) * mint(2).pow(k);
  }
  cout << ans.val() << '\n';
}