"""

r ** j = n

"""

import math
import sys
from sys import stdin

dp = [0] * (10**6+1)

for i in range(1,len(dp)):
    for j in range(2*i,len(dp),i):
        dp[j] = max(dp[j] , dp[i] + 1)

#print (dp)

N = int(stdin.readline())
A = list(map(int,stdin.readline().split()))

x = 0
for a in A:
    x ^= dp[a]

if x == 0:
    print ("black")
else:
    print ("white")