#!/usr/bin/perl

my $previous;

while (my $line = <STDIN>) {
	if ($line =~ /^(.*)\t(.*)$/) {
		if ($previous eq $1) {
			print "$2";
		} else {
			if (defined $previous) {
				print "\n"
			}
			print "$1\t$2";
		}
		$previous = $1;
	}
}

print "\n";