def Smallest_Prime_Factor(N):
    """0,1,2,...,Nの最小の素因数のリスト(0,1については1にしている)
    """

    if N==0:
        return [1]

    N=abs(N)
    L=list(range(N+1))
    L[0]=L[1]=1

    x=4
    while x<=N:
        L[x]=2
        x+=2

    x=9
    while x<=N:
        if L[x]==x:
            L[x]=3
        x+=6

    x=5
    Flag=0
    while x*x<=N:
        if L[x]==x:
            y=x*x
            while y<=N:
                if L[y]==y:
                    L[y]=x
                y+=x<<1
        x+=2+2*Flag
        Flag^=1

    return L

def Faster_Prime_Factorization(N,L):
    """

    L:Smallest_Prime_Factors(N)で求めたリスト
    """
    N=abs(N)

    D=[]
    while N>1:
        a=L[N]
        k=0
        while L[N]==a:
            k+=1
            N//=a
        D.append([a,k])
    return D
#==================================================
N=int(input())
A=list(map(int,input().split()))

L=Smallest_Prime_Factor(max(A))

G=0
for a in A:
    X=0
    for p,e in Faster_Prime_Factorization(a,L):
        X+=e
    G^=X

print("white" if G else "black")