use strict;
use warnings;

my @lines = reverse(<DATA>);

my %test;
foreach (@lines) {
    my ($name, $number) = split / /; 
    $test{$name} = $number;
}

print %test;

__DATA__
nick 5
nick 10
nick 20
john 78
erik 9
erik 12

##</code><code>##

nick5
john78
erik9