#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using mint = atcoder::modint998244353;
using ll = long long;

//enumeration<mint> enu(200000);のように宣言する
template<class T> struct enumeration{
    int N;
    vector<T> fact, inv;
    enumeration() : N(0), fact(1, 1), inv(1, 1) {}
    enumeration(int _n) : N(_n), fact(_n + 1), inv(_n + 1) {
        fact[0] = 1;
        for(int i = 1; i <= N; i++) fact[i] = fact[i - 1] * i;
        inv[N] = T(1) / fact[N];
        for(int i = N; i >= 1; i--) inv[i - 1] = inv[i] * i;
    }
    void expand(int lim){
        fact.resize(lim + 1);
        inv.resize(lim + 1);
        for(int i = N + 1; i <= lim; i++) fact[i] = i * fact[i - 1];
        inv[lim] = T(1) / fact[lim];
        for(int i = lim; i >= N + 2; i--) inv[i - 1] = i * inv[i];
        N = lim;
    }
    T Per(int n, int k){
        if(k > n) return 0;
        if(n > N) expand(n);
        return fact[n] * inv[n - k];
    }
    T C(int n, int k){
        if(n < 0 || k < 0 || k > n) return 0;
        if(n > N) expand(n);
        return fact[n] * inv[n - k] * inv[k];
    }
    T H(int n, int k){
        if(n ==0 && k == 0) return 1;
        if(n <= 0 || k < 0) return 0;
        return C(n + k - 1, k);
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    enumeration<mint> enu(2005);
    int n;
    string s;
    cin >> n >> s;
    int cnt = 0;
    reverse(s.begin(), s.end());
    while(!s.empty() && s.back() == '1') cnt++, s.pop_back();
    reverse(s.begin(), s.end());
    const int m = s.size();
    vector<mint> dp(1);
    dp[0] = 1;
    for(int i = 1; i < m; i++){
        vector<mint> ndp(i + 1);
        if(s[i] == '0'){
            vector<mint> imos(i + 2);
            for(int j = 0; j < i; j++){
                /*for(int k = 0; k <= i; k++){
                    ndp[max(k, j + 1)] += dp[j];
                }*/
                imos[j + 1] += (j + 2) * dp[j];
                imos[j + 2] -= (j + 2) * dp[j];
                imos[j + 2] += dp[j];
                imos[i + 1] -= dp[j];
            }
            for(int j = 0; j <= i; j++){
                imos[j + 1] += imos[j];
                ndp[j] += imos[j];
            }
        }else{
            for(int j = 0; j < i; j++){
                ndp[j] += (i - j) * dp[j];
            }
        }
        swap(dp, ndp);
    }
    mint ans = enu.Per(n, cnt);
    ans *= accumulate(dp.begin(), dp.end(), mint(0));
    cout << ans.val() << '\n';
}