while(<STDIN>) {
	chomp;
	($class, $seqid) = split(/\s+/, $_);

	#$Class2seqs{$class} is a pointer to an array
	push(@{ $Class2seqs{$class} }, $seqid);
}


for $classnm ( keys %Class2seqs ) {
	print "--- list of seqs in $classnm --- \n";
	print "@{ $Class2seqs{$classnm}} \n";
}