import sys
input = sys.stdin.readline

def main():
    N = int(input())
    MAX = pow(10,6) + 10
    Groundy = [1]*MAX
    Groundy[1] = 0
    for i in range(2,MAX):
        val = Groundy[i] + 1
        x = i
        while x + i < MAX:
            x += i
            Groundy[x] = max(Groundy[x], val)
    #print(Groundy)
    A = list(map(int,input().split()))
    x = 0
    for a in A:
        x ^= Groundy[a]
    if x == 0:
        print("black")
    else:
        print("white")



if __name__ == "__main__":
    main()