MOD = 998244353

N = int(input())
A = input().strip()

ans = 1
i = 0

while i < N:
    j = i
    while j + 1 < N and not (A[j] == '1' and A[j + 1] == '0'):
        j += 1

    block = A[i:j + 1]

    if '0' in block and '1' in block:
        ans = ans * (len(block) + 1) % MOD

    i = j + 1

print(ans)