#!/usr/bin/perl

use strict; # https://www.perlmonks.org/?node_id=11154123
use warnings;

open my $fh, '<', \<<END or die;
nick 5
nick 10
nick 20
john 78
erik 9
erik 12
END

my %hash;
$hash{ (split)[0] } //= $_ while <$fh>;
print values %hash;