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: 5359 aggiunta 8733 sottrazione 1397 aggiunta 8521 aggiunta 2819 sottrazione 2918

Solution: 21117