#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
using mint = modint998244353;
const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	string s; cin >> s;
	reverse(all(s));
	int cnt = 0;
	mint tmp = 1;
	while (!s.empty() && '1' == s.back()) {
		tmp *= s.size();
		s.pop_back();
	}
	reverse(all(s));
	n = s.size();
	if (0 == n) {
		cout << tmp.val() << endl;
		return 0;
	}
	vector dp(n, vector<mint>(n + 1));// 0のmaxvalue
	dp[0][0] = 1;
	rep2(i, 1, n) {
		rep(j, i) {
			if ('0' == s[i]) {
				dp[i][j + 1] += dp[i - 1][j] * (j + 1);
				dp[i][j + 2] -= dp[i - 1][j] * (j + 1);
				// [j+1,i+1)
				dp[i][j + 1] += dp[i - 1][j];
				dp[i][i + 1] -= dp[i - 1][j];
			}
			else {
				dp[i][j + 0] += dp[i - 1][j] * (i - j);
				dp[i][j + 1] -= dp[i - 1][j] * (i - j);
			}
		}
		rep(j, n)dp[i][j + 1] += dp[i][j];
	}
	mint ans =0;
	rep(i, n)ans += dp[n - 1][i];
	ans *= tmp;
	cout << ans.val() << endl;
	return 0;
}