#include <bits/stdc++.h>
using namespace std;
using ll = long long;

template<const unsigned int MOD> struct prime_modint {
    using mint = prime_modint;
    unsigned int v;
    prime_modint() : v(0) {}
    prime_modint(unsigned int a) { a %= MOD; v = a; }
    prime_modint(unsigned long long a) { a %= MOD; v = a; }
    prime_modint(int a) { a %= (int)(MOD); if(a < 0)a += MOD; v = a; }
    prime_modint(long long a) { a %= (int)(MOD); if(a < 0)a += MOD; v = a; }
    static constexpr int mod() { return MOD; }
    mint& operator++() {v++; if(v == MOD)v = 0; return *this;}
    mint& operator--() {if(v == 0)v = MOD; v--; return *this;}
    mint operator++(int) { mint result = *this; ++*this; return result; }
    mint operator--(int) { mint result = *this; --*this; return result; }
    mint& operator+=(const mint& rhs) { v += rhs.v; if(v >= MOD) v -= MOD; return *this; }
    mint& operator-=(const mint& rhs) { if(v < rhs.v) v += MOD; v -= rhs.v; return *this; }
    mint& operator*=(const mint& rhs) {
        v = (unsigned int)((unsigned long long)(v) * rhs.v % MOD);
        return *this;
    }
    mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
    mint operator+() const { return *this; }
    mint operator-() const { return mint() - *this; }
    mint pow(long long n) const {
        assert(0 <= n);
        mint r = 1, x = *this;
        while (n) {
            if (n & 1) r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }
    mint inv() const { assert(v); return pow(MOD - 2); }
    friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; }
    friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; }
    friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; }
    friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; }
    friend bool operator==(const mint& lhs, const mint& rhs) { return (lhs.v == rhs.v); }
    friend bool operator!=(const mint& lhs, const mint& rhs) { return (lhs.v != rhs.v); }
    friend std::ostream& operator << (std::ostream &os, const mint& rhs) noexcept { return os << rhs.v; }
};
//using mint = prime_modint<1000000007>;
using mint = prime_modint<998244353>;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    string s;
    cin >> n >> s;
    mint ans, d = 1;
    for(int i = 1; i <= n; i++){
        vector<array<mint,2>> dp(n + 2, {0, 0});
        vector<mint> cum0(n + 2);
        mint s0 = 1, s1;
        dp[0][0] = 1;
        cum0[1] = 1;
        /*for(int j = 0; j < n; j++){
            for(int k = j + 1; k <= n; k++){
                dp[k][(k >= i && k - i >= j && s[k - i] == '1')] += dp[j][0];
                dp[k][1] += dp[j][1];
            }
        }*/
        /*for(int j = 0; j < n; j++){
            dp[j + 1][0] += 2 * dp[j][0];
            dp[j + 1][1] += 2 * dp[j][1];
            if(j + i <= n && s[j] == '1'){
                dp[j + i][0] -= dp[j][0];
                dp[j + i + 1][0] += dp[j][0];
                dp[j + i][1] += dp[j][0];
                dp[j + i + 1][1] -= dp[j][0];
            }
        }*/
        for(int j = 1; j <= n; j++){
            if(j >= i && s[j - i] == '1'){
                dp[j][0] = s0 - cum0[j - i + 1];
                dp[j][1] = cum0[j - i + 1] + s1;
            }else{
                dp[j][0] = s0;
                dp[j][1] = s1;
            }
            cum0[j + 1] = cum0[j] + dp[j][0];
            s0 += dp[j][0], s1 += dp[j][1];
        }
        //cerr << dp[0][0] << " " << dp[0][1] << '\n';
        //cerr << dp[1][0] << " " << dp[1][1] << '\n';
        //cerr << dp[2][0] << " " << dp[2][1] << '\n';
        //cerr << dp[3][0] << " " << dp[3][1] << '\n';

        //cerr << dp[n][0] << " " << dp[n][1] << '\n';
        ans += d * dp[n][1];
        d += d;
    }
    cout << ans << '\n';
}