import sys
input = sys.stdin.readline
N = int(input())
A = list(map(int, input().split()))
ma = -1
ans = ""
for i in range(1<<12):
    W = 0
    B = 0
    flag = True
    tmp = []
    for j in range(N):
        a = A[j]
        if a|i==i:
            B |= a
            tmp.append("B")
        elif a&i==0:
            W |= a
            tmp.append("W")
        else:
            flag = False
    if flag:
        if ma<B*W:
            ma = B*W
            ans = tmp
print(ma)
print("".join(ans))