Arjun bought seven grocery items A, B, C, D, E, F, and G each having a different weight. Item D is heavier than only three items but lighter than exactly three items. Item G is lighter than A but heavier than B and C. The second lightest item weighs exactly half of the heaviest item. Item F is neither the heaviest nor the second heaviest. Item C is the lightest among all. Item A weighs 18 kg and is not the heaviest. Number of items heavier than E is one less than the number items lighter than F.