my $overlap = {};
foreach $Cluster_Num (keys %HoCl){
        my @members=@{$HoCl{$Cluster_Num}};
        my $count = scalar(@members);
        for (my $i=0;$i<$count;$i++){
                for (my $j=$i+1;$j<$count;$j++) {
                $overlap -> {$members[$i]} -> {$members[$j]} = 0;
                $overlap -> {$members[$i]} -> {$members[$j]} ++;
                $overlap -> {$members[$j]} -> {$members[$i]} ++;
}
}
}