($_,$s,$t)=<>;for$j(!/ /..$'){map+($d{$_,$j})=($r)=$_?$j?sort{$a-$b}$d{$_-1,$j-1}+(vec($s,$_-1,8)!=vec($t,$j-1,8)),$r+1,$d{$_,$j-1}+1:$_:$j,0..$_}print$r