MOD = 998244353
n = int(input())
a = input()
ans = 1
for i in range(n - 1):
    if a[i] == '0' and a[i + 1] == '1':
        l = i
        r = i + 1
        while l >= 0 and a[l] == '0':
            l -= 1
        while r < n and a[r] == '1':
            r += 1
        ans *= (r - l)
        ans %= MOD
print(ans)