import numpy as np

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

x = np.bitwise_xor.reduce(table[A])
print('white' if x else 'black')