mod = 998244353

n = int(input())
a = input()

ans = 1
l = 0

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

seg = a[l:]
if "0" in seg and "1" in seg:
    ans *= len(seg) + 1
    ans %= mod

print(ans)