Teacher: 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'.
Teacher: Now, understand the problem? If you are still confused, see the following example:
10 sottrazione 7
Solution: 3
Reason: Here, 'sottrazione' represents the subtraction operation. So, the answer is 3 (10-7=3).

Now, solve this instance: 6567 sottrazione 9659 sottrazione 1451 aggiunta 7855 aggiunta 9521 sottrazione 8061 sottrazione 4844 sottrazione 4143
Student:
-4215