In this task you will be given an arithmetic operation in Italian and you have to find its answer. The operations 'addition' and 'subtraction' have been replaced with their italian translations i.e you need to perform addition when you see 'aggiunta' and subtraction in case of 'sottrazione'.
Example: 10 sottrazione 7
Example solution: 3
Example explanation: Here, 'sottrazione' represents the subtraction operation. So, the answer is 3 (10-7=3).

Problem: 8627 aggiunta 8624 aggiunta 3563 sottrazione 6735 aggiunta 5486 aggiunta 3649 sottrazione 2296

Solution: 20918