n=int(input())
a=list(map(int,input().split()))
ans=(0,["W"]*n)
l=13
for i in range(1<<l):
  w=0
  b=0
  c=[]
  for v in a:
    if i|v==i:
      w|=v
      c+=["W"]
    else:
      b|=v
      c+=["B"]
  if w==i and w&b==0:
    ans=max(ans,(w*b,c))
print(ans[0])
print("".join(ans[1]))