{
'A' => {
        'B' => 'C',
        'D' => 'E'
                    },
'F' => {
        'B' => 'G',
        'D' => 'H'
                    },
'I' => {
        'B' => 'G',
        'D' => 'H'
                    },
'J' => {
        'B' => 'C',
        'D' => 'F'
                    },

    }
}

[download]
I need to check for duplicate F ,I based on its inner pairing of G and H (G and H is common for B and D respectively in F and I, (They make a common duplicate pair) The final output count structure is like this: 
 { 
   'B' => { 'C' => 2 ,'G' => 1}             # see G's and H's count is
+ 1  Taking G and H's pair only once.  C is 2 because C, E and C,F do 
+not make a pair, C comes twice and E and F once
   'D' => { 'E' => 1, 'H' => 1, 'F'=>1, }   # see H's count is 1
}

[download]

In reply to Perl hash iteration performance by perlronm

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