foreach (@ARGV) {
	open my $fh, '<', $_ or die $!;
	while ( my $line = <$fh> ) {
		next unless my @p = $line =~ /^(chr.+?)\t+(\d+)\t+(\d+)/;

		$minmax{ $p[0] }{min} //= $p[1];
		$minmax{ $p[0] }{max} //= $p[2];

		if ( $p[1] < $minmax{ $p[0] }{min} ) {
			$minmax{ $p[0] }{min} = $p[1];
		}

		if ( $p[2] > $minmax{ $p[0] }{max} ) {
			$minmax{ $p[0] }{max} = $p[2];
		}
	}
	close $fh;
}