#!/usr/bin/env perl
use 5.010;
use strict;
use warnings;
use Data::Dumper;

use local::lib 'lib';

use XML::Twig;

my $string = <<EOF;
<Person name="Brian">
    <Phones>
        <Phone name="cell" number="5551112233" />
        <Phone name="cell" number="5557778899" />
        <Phone name="home" number="5554441122" />
    </Phones>
</Person>
EOF

my $twig = XML::Twig->new;
$twig->parse($string);
my @nodes = $twig->findnodes('/Person/Phones/Phone');
my @cellphones_nrs = map {
        $_->att('number')
    }
    grep {
        defined $_->att('name')
     && $_->att('name') eq 'cell'
     && defined $_->att('number')
    } @nodes;

say "Cellphone: $cellphones_nrs[-1]"
    if @cellphones_nrs;