import sys
from collections import deque

N = int(input().strip())
A = input().strip()
MOD = 998244353

if A[0] == '0':
    dp_0 = 1
    dp_1 = 1
else:   
    dp_0 = 0
    dp_1 = 1

for i in range(1, N):
    if A[i-1] == '1' and A[i] == '0':
        new_dp_0 = (dp_0 + dp_1) % MOD
    else:
        new_dp_0 = dp_0

    new_dp_1 = (dp_0 + dp_1) % MOD
    dp_0 = new_dp_0
    dp_1 = new_dp_1

if A[-1] == '0':
    ans = dp_0
else:
    ans = (dp_0 + dp_1) % MOD

print(ans)