use strict;
use warnings;

open(my $N148,'<',"148Nsorted.bed") or die $!;

open(my $N162,'<',"162Nsorted.bed") or die $!;

open(my $N174,'<',"174Nsorted.bed") or die $!;

open(my $N175,'<',"175Nsorted.bed") or die $!;

my ($chr148, $start148, $end148) = scan($N148);
my ($chr162, $start162, $end162) = scan($N162);
my ($chr174, $start174, $end174) = scan($N174);
my ($chr175, $start175, $end175) = scan($N175);

my ($minstart, $maxstart, $minend, $maxend);

while(defined($chr148)) {
    $minstart = $start148;
    $maxstart = $start148;
    $minend = $end148;
    $maxend = $end148;
    while(defined($chr162) and $chr162 lt $chr148) {
        ($chr162, $start162, $end162) = scan($N162);
    }
    while(defined($chr162) and $chr162 eq $chr148) {
        $minstart = $start162 if($start162 < $minstart);
        $maxstart = $start162 if($start162 > $maxstart);
        $minend = $end162 if($end162 < $minend);
        $maxend = $end162 if($end162 > $maxend);
        if($maxstart <= $minend) {
            while(defined($chr174) and $chr174 lt $chr148) {
                ($chr174, $start174, $end174) = scan($N174);
            }
            while(defined($chr174) and $chr174 eq $chr148) {
                $minstart = $start174 if($start174 < $minstart);
                $maxstart = $start174 if($start174 > $maxstart);
                $minend = $end174 if($end174 < $minend);
                $maxend = $end174 if($end174 > $maxend);
                if($maxstart <= $minend) {
                    while(defined($chr175) and $chr175 lt $chr148) {
                        ($chr175, $start175, $end175) = scan($N175);
                    }
                    while(defined($chr175) and $chr175 eq $chr148) {
                        $minstart = $start175 if($start175 < $minstart);
                        $maxstart = $start175 if($start175 > $maxstart);
                        $minend = $end175 if($end175 < $minend);
                        $maxend = $end175 if($end175 > $maxend);
                        if($maxstart <= $minend) {
                            print "$chr148 $minstart $maxend\n";
                        }
                        ($chr175, $start175, $end175) = scan($N175);
                    }
                }
                ($chr174, $start174, $end174) = scan($N174);
            }
        }
        ($chr162, $start162, $end162) = scan($N162);
    }
    ($chr148, $start148, $end148) = scan($N148);
}



close($N148);
close($N162);
close($N174);
close($N175);

exit(0);


sub scan {
    my ($fh) = @_;

    my $line = <$fh>;
    return() unless($line);
    return(split(/\t/, $line));
}