use strict; use warnings;
use File::Slurp qw(read_file);

my $sfile = shift;
my $dbfile = shift;

my %series = map {/^(rs\d{1,18})\s+(rs\d{1,18})$/, $1=>$2} read_file $sfile;
my %dbpairs = map {/\s+(rs\d{1,18})\s+/, $1=>1} grep {/rs\d{1,18}/} read_file $dbfile;

foreach my $pair (sort keys %series){
	if(exists $dbpairs{$pair} && exists $dbpairs{$series{$pair}}){
		print "$pair $series{$pair}\n";
	}
}