unless (open(INPUT, "$inputfile"))
    {
    print "ERROR: Can't open file for reading : $!\n";

    }

##</code><code>##

# splitting on tab character

    my @data = split("\t", $_);

    # assigning varables

    my $did1 = $data[0];
    my $did2 = $data[1];
    my $score1 = $data[2];
    my $score2 = $data[3];

##</code><code>##

my ( $did1,$did2,$score1,$score2 ) = (split("\t", $_))[0..3];