from math import sqrt, ceil
def Sieve(n):
    lst = [True] * (n + 1)
    S = set()
    for i in range(2, ceil(sqrt(n)) + 1):
        if lst[i]:
            for j in range(2 * i, n + 1, i):
                lst[j] = False
    for i in range(2, n + 1):
        if lst[i]:
            S.add(i)
    return S

N = int(input())
A = list(map(int, input().split()))
M = max(A)
D = [0] * (M + 1)

for p in Sieve(M):
    now = p
    while now <= M:
        for i in range(now, M + 1, now):
            D[i] += 1
        now *= p

ans = 0
for a in A:
    ans ^= D[a]

print("white") if ans else print("black")