#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<n; i++)
#define debug 0
#define YES cout << "Yes" << endl;
#define NO cout << "No" << endl;
using ll = long long;
using ld = long double;
const int mod = 998244353;
const int MOD = 1000000007;
const double pi = atan2(0, -1);
#include <time.h>
#include <chrono>

int main() {
	int N;
	string S;
	cin >> N >> S;
	vector<ll> dp(N + 1, 0);
	ll c = 0;
	rep(i, N) {
		if (S[i] == '0') {
			c++;
			dp[i + 1] += dp[i];
		}
		if (S[i] == '1') {
			if (dp[i] == 0) {
				dp[i + 1] = 1;
			}
			else {
				dp[i + 1] += dp[i] * (c + 2);
			}
			c = 0;
		}
		dp[i + 1] %= mod;
	}

	cout << dp[N] << endl;
}