N = int(input())
A = list(map(int, input().split()))
x = 0
for a in A:
    i = 2
    ans = dict()
    n = a
    while i * i <= a:
        while n % i==0:
            n = n // i
            if i in ans:
                ans[i] += 1
            else:
                ans[i] = 1
        i += 1
    if n != 1:
        ans[n] = 1
    res = 0
    for c in ans:
        res += ans[c]
    x ^= res
print(["white", "black"][x == 0])