mod = 998244353

n = int(input())
s = input().strip()

a = []
for c in s:
    if a and a[-1][0] == c:
        a[-1][1] += 1
    else:
        a.append([c, 1])

ans = 1

for i in range(len(a) - 1):
    if a[i][0] == '0' and a[i + 1][0] == '1':
        ans = ans * (a[i][1] + a[i + 1][1] + 1) % mod

print(ans)