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