open IN, '<', $ARGV[0];
my %hash1;
while (<IN>) {
    next unless ( $_ =~ m/^\@HWI/ );
    my ($header) = split(/ /, $_);
    $hash1{$header} = 1;   
}
close IN;

open IN2, '<', $ARGV[1];
my %hash2;
while (<IN2>) {
    next unless ( $_ =~ m/^\@HWI/ );
    my ($header) = split(/ /, $_);
    $hash2{$header} = 1;   
}
close IN;