from collections import deque
N = int(input())
A = list(map(int,input().split()))
que = deque([(0,0,"")])
results = []
while que:
    w,b,s = que.popleft()
    if len(s)==N:
        results.append((w,b,s))
        continue
    i = len(s)
    a = A[i]
    if w&a==0:
        b1 = b|a
        s1 = s+"B"
        que.append((w,b1,s1))
    if b&a==0:
        w1 = w|a
        s1 = s+"W"
        que.append((w1,b,s1))
m = 0
ans = ""
for w,b,s in results:
    if w*b>m:
        m = w*b
        ans = s
print(m)
print(ans)