N = int(input())
A = list(map(int,input().split()))
C = 10 ** 6 + 1
dat = [0] * C
for i in range(2,C):
    if dat[i] == 0:
        for j in range(i,C,i):
            dat[j] += 1
        now = i * i
        while now < C:
            for j in range(now,C,now):
                dat[j] += 1
            now *= i
grundy = 0
for a in A:
    grundy ^= dat[a]
if grundy:
    print("white")
else:
    print("black")