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

# 素数列挙
mx = 10 ** 6
div = [0] * (mx + 1)
div[1] = 1
for i in range(2, mx + 1):
    if div[i]:
        continue
    for j in range(i, mx + 1, i):
        div[j] = i

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

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