#include <iostream>
#include <vector>

int main() {
	int N;
	std::string S;
	std::cin >> N >> S; S += '0';
	long long ans = 1, last = N, mod = 998244353;
	for (int i = 0; i <= N; ++i) {
		if (S[i] == '0') {
			last = i;
			break;
		}
	}
	for (int i = last + 1; i <= N; ++i) {
		if (S[i - 1] > S[i]) {
			ans *= i - last + 1;
			ans %= mod;
			last = i;
		}
	}
	std::cout << ans << '\n';
}