C:\monks\calc_mass>perl calc_molecularmass.pl
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$VAR1 = {
          'H' => 6,
          'O' => 1,
          'C' => 6
        };
----------------
----------------
$VAR1 = {
          'H' => 9,
          'C' => 6
        };
----------------
----------------
$VAR1 = {
          'Hg' => 1
        };
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C:\monks\calc_mass>