#ex_07-4
#Learning Perl Appendix A, Exercise 7.4
while (<STDIN>) {
    chomp;
    ($gcos) = (split /:/)[4];
    ($real) = split(/,/, $gcos);
    ($first) = split(/\s+/, $real);
    $seen{$first}++;
}
foreach (keys %seen) {
    if ($seen{$_} > 1) {
        print "$_ was seen $seen{$_} times\n";
    }
}