N = int(input())
A = map(int, input().split())
MAX = 10 ** 6
table = [0] * (MAX + 1)
for i in range(2, MAX + 1):
    if not table[i]:
        j = i
        while j <= MAX:
            for k in range(j, MAX + 1, j):
                table[k] += 1
            j *= i

x = 0
for a in A:
    x ^= table[a]
print('white' if x else 'black')