n = int(input())

m = 10**6+5
l = [set([0]) for i in range(m)]
grundy = [-1]*m
grundy[1] = 0
for i in range(2,m):
    for j in range(m):
        if j in l[i]:
            continue
        grundy[i] = j
        break
    for j in range(i*2,m,i):
        l[j].add(grundy[i])

ans = 0
A = list(map(int,input().split()))
for a in A:
    ans ^= grundy[a]
if ans:
    print("white")
else:
    print("black")