N = int(input())
A = list(map(int,input().split()))
ans = "B"*N
m = 0
for n in range(4001):
    W = 0
    B = 0
    row = ""
    for a in A:
        flag = True
        for k in range(14):
            if ((n>>k)&1)<((a>>k)&1):
                flag = False
                break
        if flag:
            W = W|a
            row += "W"
        else:
            B = B|a
            row += "B"
    if m<W*B:
        m = W*B
        ans = row
print(m)
print(ans)