#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
int n; string s; 
const int mod = 998244353;
const int N = 4005;
int p[N];
int dp[N][2];
int unsetpref[N];

int calc(int x){
    dp[0][0] = 1;
    dp[0][1] = 0;
    int pref = 0;
    unsetpref[0] = 1;
    
    for (int i = 1; i <= n; i++){
        dp[i][0] = p[i - 1];
        //consider previously set bit 
        dp[i][1] = pref;
        if (i > x && s[i - x] == '1'){
            dp[i][1] += unsetpref[i - x - 1];
            dp[i][1] %= mod;
        }
        
        pref += dp[i][1]; pref %= mod;
        unsetpref[i] = unsetpref[i - 1] + dp[i][0] - dp[i][1];
        unsetpref[i] %= mod; if (unsetpref[i] < 0) unsetpref[i] += mod;
    }
    
    return dp[n][1];
}

void Solve() 
{
    cin >> n >> s;
    s = "0" + s;
    
    p[0] = 1;
    for (int i = 1; i < N; i++) p[i] = p[i-1] * 2 % mod;
    
    int ans = 0;
    
    for (int bi = 0; bi < n; bi++){
        int ways = calc(bi);
        ans += ways * p[bi] % mod;
        ans %= mod;
    }
    
    cout << ans << "\n";
}

int32_t main() 
{
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
  //  cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        //cout << "Case #" << i << ": ";
        Solve();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
   // cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}