#!/usr/bin/perl
use strict;
use warnings;
my $input = '';
my %nme   = ();
my $fn    = '';
my $ln    = '';

while() {
    print "enter the name\n";
    chomp($input=<STDIN>);
    
    if($input ne '') {
        ($fn, $ln) = split('',$input);
        print "$fn, $ln\n";
        $nme{$ln} = $fn;
    } else { 
        last;
    }
    
    foreach my $lastname(sort keys %nme) {
        print "$lastname, $nme{$lastname}\n";
    }