use strict;
use warnings;
use feature 'say';
use Data::Dumper;
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;

use Hash::Merge 'merge';

my $VAR1 = {
          'Tim' => {
                    'abc' => 7,
                 'def' => 7,
             'ghi' => 0
                    },
          'Adam' => {
                 'abc' => 0,
                 'def' => 0,
                 'ghi' => 0
                    },
          'keas' => {
                 'abc' => 0,
             'def' => 0,
             'ghi' => 0
                    }
};

my $VAR2 = {
          'Dav' => {
                'jkl' => 12,
             'mno' => 34,
             'pqr' => 45
                    },
          'Adam' => {
                'jkl' => 7,
            'mno' => 0,
            'pqr' => 7
                     }
};

my $output = merge($VAR1, $VAR2);

say Dumper $output;

##</code><code>##

$VAR1 = {
  'Adam' => {
    'abc' => 0,
    'def' => 0,
    'ghi' => 0,
    'jkl' => 7,
    'mno' => 0,
    'pqr' => 7
  },
  'Dav' => {
    'jkl' => 12,
    'mno' => 34,
    'pqr' => 45
  },
  'Tim' => {
    'abc' => 7,
    'def' => 7,
    'ghi' => 0
  },
  'keas' => {
    'abc' => 0,
    'def' => 0,
    'ghi' => 0
  }
};