n=int(input())
L=list(map(int,input().split()))

T=0
for e in L:
  T|=e

ans=0
ANS=["W"]*n
for OR in range(2**14):
  B,W=0,0
  TMP=["W"]*n
  
  for i in range(n):
    if OR|L[i]==OR:
      B|=L[i]
      TMP[i]="B"
    else:
      W|=L[i]
  if B==OR and B&W==0:
    if ans<B*W:
      ans=B*W
      ANS=TMP
      
print(ans)
print("".join(ANS))