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 input: 10 sottrazione 7
Example output: 3
Example explanation: Here, 'sottrazione' represents the subtraction operation. So, the answer is 3 (10-7=3).
Q: 2534 aggiunta 7456 aggiunta 3166 aggiunta 4581 sottrazione 4891 aggiunta 5921 aggiunta 5737 aggiunta 3946 sottrazione 7422
A:
21028