import sys


MOD = 998244353


def main() -> None:
    input = sys.stdin.readline
    n = int(input())
    s = input().strip()

    ans = 1
    i = 0

    while i < n:
        if s[i] == "1":
            i += 1
            continue

        j = i
        while j < n and s[j] == "0":
            j += 1

        if j == n:
            break

        k = j
        while k < n and s[k] == "1":
            k += 1

        ans = ans * (k - i + 1) % MOD
        i = k

    print(ans)


if __name__ == "__main__":
    main()