MOD = 998244353

N = int(input())
S = input().strip()

runs = []
i = 0
while i < N:
    j = i
    while j < N and S[j] == S[i]:
        j += 1
    runs.append((S[i], j - i))
    i = j

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

print(ans)