N = int(input())
A = list(map(int, input().split()))
m = 0
ans = ""
for n in range(1<<14):
    w = 0
    b = 0
    s = ""
    for i in range(N):
        if n&A[i]==0:
            b |= A[i]
            s += "B"
        else:
            w |= A[i]
            s += "W"
    if w&b==0 and w*b>m:
        m = w*b
        ans = s
print(m)
print(ans)