Advice on any two pair summation algorithms

Example: Apple: 3 bananas: 5 watermelons: 1 pineapple: 8 cherries: 10 any two fruits can be exchanged for 1 gold coin, for example, how much gold coins can be exchanged for 1 apple + 1 banana and 1 gold coin. Example:
Apple: 3
Bananas: 5
Watermelon: 1
Pineapple: 8
Cherries: 10

You can change one gold coin for any two types of fruits, for example, 1 apple + 1 banana = 1 gold coin.

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Example:
Apple: 3
Bananas: 5
Watermelon: 1
Pineapple: 8
Cherries: 10

You can change one gold coin for any two types of fruits, for example, 1 apple + 1 banana = 1 gold coin.