merging two hashes

[sen]

hell monks,

I need in my script, to merge the first element of each inner hash into array, but i didn't get the output what i need. i need the output as @a=(a g h i g h i)

my $s = { 'aa' => {
                '1' => ['a'],
                '2' => ['b','c','d'],
                '3' => ['f'],
                '4' => ['g']
                },
        'bb' => {
                '1'  => ['g','h','i'],
                '2'  => ['s','a','d']
                },
        'cc' => {
               '1'  => ['g','h','i'],
               '2'  => ['s','a','d']
                }
           };
my @a= ($s->{aa}->{'1'},$s->{bb}->{'1'},$s->{cc}->{'1'});
print @a;

thanks in advance