import sys
input = sys.stdin.readline

N=int(input())
A=list(map(int,input().split()))

ANS=0
IND=["W"]*N
for i in range(1<<12):
    rest=((1<<12)-1)^i

    flag=1

    W=0
    H=0

    L=[""]*N

    for ix in range(N):
        a=A[ix]
        if ((a & i) == 0) and ((a&rest)==a):
            W|=a
            L[ix]="W"
            continue
        if ((a & i) == a) and ((a&rest)==0):
            H|=a
            L[ix]="B"
            continue
        flag=0

    #print(i,rest,W,H,flag)
    #print(flag,W,H)

    if flag:
        if W*H>ANS:
            ANS=W*H
            IND=L[:]

print(ANS)
print("".join(IND))