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

fact = [0]*(M+1)

for i in range(2, M+1):
    if fact[i]:
        continue
    fact[i] = 1
    for j in range(i*i, M+1, i):
        if not fact[j]:
            fact[j] = j//i

v = 0
for a in A:
    ct = 0
    ind = a
    while ind > 1:
        ind = fact[ind]
        ct += 1
    v ^= ct

print('while' if v else 'black')