Any suggestions to did this?

Example 1:

shop1,sale = 2 inventory = 9
shop2,sale =10 inventory = 1
shop3,sale = 4 inventory = 0
Total QTY,sale = 16 inventory = 10


Transfer:
shop1 to shop2 = 3 pcs
shop1 to shop3 = 3 pcs

Desired:

shop1,sale = 2 inventory = 3
shop2,sale =10 inventory = 4
shop3,sale = 4 inventory = 3
Total QTY,sale = 16 inventory = 10

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Example 2:

shop1,sale = 10 inventory = 5
shop2,sale = 9 inventory = 1
shop3,sale = 4 inventory = 11
Total QTY,sale = 23 inventory = 17


Transfer:
shop3 to shop2 = 5 pcs

Desired:

shop1,sale = 10 inventory = 5
shop2,sale = 9 inventory = 6
shop3,sale = 4 inventory = 6
Total QTY,sale = 23 inventory = 17
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