#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

using namespace std;
using u64 = unsigned long long;

constexpr int MOD = 998244353;

inline int add(int x, int y) { return x + y >= MOD ? x + y - MOD : x + y; }
inline int mul(int x, int y) { return x * (u64)y % MOD; }

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int N;
    string s;
    cin >> N >> s;

    vector f(N, vector<int>(N)), sum(N, vector<int>(N));
    if (s[0] == '1') {
        f[0][0] = N;
        ranges::fill(sum[0], N);
    } else {
        for (int i = 0; i < N; ++i) {
            f[0][i] = 1;
            sum[0][i] = i + 1;
        }
    }

    for (int i = 1; i < N; ++i) {
        for (int j = 0; j < N; ++j) {
            if (s[i] == '0') {
                f[i][j] = add(f[i][j], sum[i - 1][j]);
                if (j + 1 < N)
                    f[i][j] = add(f[i][j], mul(f[i - 1][j + 1], j + 1));
            } else
                f[i][j] = add(f[i][j], mul(f[i - 1][j], N - i - j));

            sum[i][j] = add(j > 0 ? sum[i][j - 1] : 0, f[i][j]);
        }
    }

    cout << f.back()[0] << '\n';
    return 0;
}