import sys
input = sys.stdin.readline
MOD = 998244353
N = int(input())
A = input().strip()
blocks = []
i = 0
while i < N:
    j = i
    while j < N and A[j] == A[i]:
        j += 1
    blocks.append((A[i], j - i))
    i = j
ans = 1
for k in range(len(blocks) - 1):
    if blocks[k][0] == '0' and blocks[k+1][0] == '1':
        ans = ans * (blocks[k][1] + blocks[k+1][1] + 1) % MOD
print(ans)