#include <bits/stdc++.h>
using namespace std;
using LL = long long;
constexpr LL mod = 998244353;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    string s;
    cin >> n >> s;
    LL ans = 0;
    for (LL k = 1, p = 1; k <= n; k += 1, p = p * 2 % mod) {
        vector<LL> f(n + 1);
        vector<LL> g(n + 1);
        g[0] = 1;
        for (int i = 1; i <= n; i += 1) {
            if (i < k or s[i - k] == '0') {
                g[i] = g[i - 1];
                f[i] = f[i - 1];
            } else {
                f[i] = (f[i - 1] + g[i - k]) % mod;
                g[i] = (g[i - 1] + mod - g[i - k]) % mod;
            }
            f[i] = (f[i] + f[i - 1]) % mod;
            g[i] = (g[i] + g[i - 1]) % mod;
        }
        ans = (ans + (f[n] + mod - f[n - 1]) * p) % mod;
    }
    cout << ans;
}