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

# 素数列挙
mx = 10 ** 6
isprime = [True] * (mx + 1)
prime_list = []
isprime[0], isprime[1] = False, False
for i in range(2, mx):
    if isprime[i] == False:
        continue
    prime_list.append(i)
    j = 2 * i
    while j <= mx:
        isprime[j] = False
        j += i

#素因数分解
cnt = [0] * N
for p in prime_list:
    for i in range(N):
        while A[i] % p == 0:
            cnt[i] += 1
            A[i] //= p

# XOR
x = 0
for c in cnt:
    x ^= c
print(["black", "white"][x > 0])