@g=map{$_=sprintf"%04o",$_;$_=~y@0-7@A-H@;$_}0..4095;for($|=1;@g>1;){print$f=$g
[@g*rand],$";($S=<>)=~/^[0-4]{2}$/?(@g=grep{$d=4-($a=($f^($e=$_))=~y@\0@@);$d-=
($c=index$e,$_)<0||(substr($e,$c,1)="")for(split'',$f);$&eq$a.$d}@g):print"\7"}