sub seq{
  my @x=split"",pop;
  my $s=pop;
  my $cc=0;
  for my $k (0..$#x-1) {
    $c = seq1($cc, $s, @x[$k..$#x]);
    $cc = ($c, $cc)[ $c < $cc ]
  }
  $cc
}
sub seq1 {
  my($cc, $s, @x) = @_;
  my $c=pos($s)=0;
  my $op=0; my $cy=0;

  for my $k (0..$#x) {

    $s =~ /$x[$k]/gc or next;

    if ($cc <= @x - $k) {       # what if we skip this char?

      my $cx = $c + seq1( $cy, substr($s, $op), @x[$k+1 .. $#x]);

      $cy = ($cx, $cy)[$cx < $cy];
    }
    $op = pos($s);
    $c++;
  }
  $c = ($cy, $c)[ $cy < $c ];
}