load'strings'
s=:' '
3 :'if.a:~:<y do.wd y rplc''@'';s end.'&dtb"1;"1(,.<@#&s"0+:(>:i.-(<:1{$a)),0,>:i.<:0{$a),.(,'   '&,)/&.>,.</.|."1 a=:rplc&(s;'@');._2(1!:1)3