R=range
I=print
J=lambda:list(map(int,input().split()))
N,*_=J()
A=J()
c=0
S=['W']*N
T=S[:]
for s in R(4096):
	a=b=0
	for i in R(N):
		if A[i]|s==s:a|=A[i];S[i]='W'
		elif not(A[i]&s):b|=A[i];S[i]='B'
		else:a=0;break
	if c<a*b:c,T=a*b,S[:]
I(c)
I(''.join(T))