MOD = 998244353
import collections


def solve(S: str) -> None:
    s = collections.deque(S)
    while s and s[0] == "1":
        s.popleft()
    while s and s[-1] == "0":
        s.pop()
    s = "".join(s).replace("10", "1 0").split()
    result = 1
    for substring in s:
        result = result * (len(substring) + 1) % MOD
    print(result)


if __name__ == "__main__":
    input()
    solve(input())