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

ans = -1
OP = []
for bit in range(1<<12):
    op = []
    W, B = 0, 0
    for i in range(N):
        if bit|A[i] == bit:
            W |= A[i]
            op.append("W")
        else:
            B |= A[i]
            op.append("B")
    if W&B == 0 and ans < W*B:
        ans = W*B
        OP = op[:]

print(ans)
print("".join(OP))