my %csahash;

my $line=<>;

while($line=<>){

if($line=~ /\b(\d\w{3})\b/){

$csahash{$1}++;

}


}


%cathhash;

my $line2=<>;

while($line2=<>){

if($line2=~/\b(\d\w{3})\b/){

$cathhash{$line2}++;

}

}



foreach my $key(keys %csahash){

if(defined $cathhash{$key}){

print "$key matches. It's values are $csahash{$key} and $cathhash{$key}\n";

}
}