N = int(input())
S = input()

mod = 998244353
ans = 1
zero = 0
one = 0

for i in range(N):
    if S[i] == "0":
        if one > 0:
            ans *= zero + one + 1
            ans %= mod
            zero = 0
            one = 0
        zero += 1
    else:
        one += 1

if zero > 0 and one > 0:
    ans *= zero + one + 1
    ans %= mod
    
print(ans)