n = int(input())
A = list(map(int, input().split()))

prime = [True for _ in range(10**6 + 1)]
prime[0] = prime[1] = False
for i in range(2, 10**6 + 1):
    if not prime[i]:
        continue
    for j in range(2 * i, 10**6 + 1, i):
        prime[j] = False

prime_num = 0
for i in range(n):
    if prime[A[i]]:
        prime_num += 1

if prime_num % 2 == 0:
    print("white")
else:
    print("black")