%h = (
	'USA' => ['Chicago', 'Washington', 'New York'],
	'Germany' => ['Frankfurt', 'Berlin'],
	'Finland' => ['Helsinki']
);

for $k (sort keys %h){
print "$k: @{$h{$k}}\n";
}


%h = (
	'USA' => {'Chicago' => undef, 'Washington' => undef, 'New York' => undef},
	'Germany' => {'Frankfurt' => undef, 'Berlin' => undef},
	'Finland' => {'Helsinki' => undef}
);

for $k (sort keys %h){
	print join ' ', $k, keys %{$h{$k}},"\n";
}