import sys
input = sys.stdin.readline
from collections import *

def c(n, r):
    if two[n]==two[r]+two[n-r]:
        return 1
    else:
        return 0

N = int(input())
B = list(map(int, input().split()))
two = [0]

for i in range(1, N+10):
    now = i
    cnt = 0
    
    while now%2==0:
        now //= 2
        cnt += 1
    
    two.append(two[-1]+cnt)
    
dp = [[0]*2 for _ in range(N+1)]
dp[0][0] = 1
MOD = 998244353

for i in range(N):
    com = c(N-1, i)
    
    if B[i] in [0, 1]:
        for j in range(2):
            nj = (j+com*B[i])%2
            dp[i+1][nj] += dp[i][j]
            dp[i+1][nj] %= MOD
    else:
        for j in range(2):
            for k in range(2):
                nj = (j+com*k)%2
                dp[i+1][nj] += dp[i][j]
                dp[i+1][nj] %= MOD

print(dp[N][1])