n = int(input())
S = list(input())
mod = 998244353

if S == ['0'] * n:
    print(0)
    exit()

ans = 1
zero_cnt = -1
for i in range(n):
    if S[i] == '0':
        if zero_cnt >= 0:
            zero_cnt += 1
    else:
        if zero_cnt >= 0:
            ans *= zero_cnt + 2
            ans %= mod
        zero_cnt = 0
print(ans)