ll@N,@A[N],B=1<<12,p,q,t,f;ll x=-1,r;rep(s,B){t=B+~s,p=q=f=0;rep(i,N){if((s&A[i])==A[i]) p|=A[i]; else if((t&A[i])==A[i]) q|=A[i]; else f=1; }if(!f&&x<p*q)x=p*q,r=s;}wt(x);rep(i,N)wtN((A[i]&r)==A[i] ? "B" : "W");