#include <stdio.h>
#include <string.h>

#define MOD 998244353LL
#define MAXN 500005

char s[MAXN];

int main() {
    int N;
    scanf("%d", &N);
    scanf("%s", s);

    long long ans = 1;
    int i = 0;

    while (i < N) {
        if (s[i] == '1') {
            // pure 1-run: contributes 1
            while (i < N && s[i] == '1') i++;
        } else {
            // zero-run
            int a = 0;
            while (i < N && s[i] == '0') {
                a++;
                i++;
            }

            // if followed by one-run, this pair contributes (a+b+1)
            if (i < N && s[i] == '1') {
                int b = 0;
                while (i < N && s[i] == '1') {
                    b++;
                    i++;
                }
                ans = (ans * (a + b + 1LL)) % MOD;
            }
            // else: trailing pure 0-run, contributes 1
        }
    }

    printf("%lld\n", ans % MOD);
    return 0;
}