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

filter = (1 << 12) - 1
vmax = 0
S = None

for mask in range(1<<12):
    W,B = 0,0
    tmp = []
    for i in range(N):
        if mask | A[i] <= mask:
            W |= A[i]
            tmp.append("W")
        else:
            B |= A[i]
            tmp.append("B")

    if W & B == 0 and W * B > vmax:
        vmax = W * B
        S = "".join(tmp)

print(vmax)
print(S)