def combmod2(n, r):
    #comb(n, r)は偶数か? True/False
    x = format(n, '032b')
    y = format(r, '032b')
    for i in range(32):
        if x[i] == '0' and y[i] == '1':
            return True
    return False


def solve(n, a):
    dp = [[0] * 2 for _ in range(n + 1)]
    dp[0][0] = 1
    mod = 998244353
    for i in range(n):
        if a[i] != -1:
            if combmod2(n, i):
                dp[i + 1][1] += dp[i][1]
                dp[i + 1][0] += dp[i][0]
            else:
                dp[i + 1][(1 + a[i]) % 2] += dp[i][1]
                dp[i + 1][a[i]] += dp[i][0]
        else:
            if combmod2(n, i):
                dp[i + 1][1] += dp[i][1]
                dp[i + 1][0] += dp[i][0]
            else:
                dp[i + 1][1] += dp[i][0] + dp[i][1]
                dp[i + 1][0] += dp[i][0] + dp[i][1]
        dp[i + 1][1] %= mod
        dp[i + 1][0] %= mod
    return dp[n][1]

n = int(input())
a = list(map(int,input().split()))
if 2 <= n <= 2 * 10 ** 5 and a.count(-1) + a.count(0) + a.count(1) == n:
    pass
else:
    raise Exception
    
print(solve(n, a))