#!/usr/bin/perl

use strict;
use sort 'stable';

my %dict;
while (<>) {
	my @words = split;
	foreach my $word (@words) {
		++$dict{$word};
	}
}

my @keys = sort { $dict{$a} <=> $dict{$b} } sort keys %dict;
foreach my $k (@keys) {
	print "$dict{$k}\t$k\n";
}