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'.
Q: 256 sottrazione 6897 aggiunta 3353 aggiunta 8899 aggiunta 9790 aggiunta 4676
A: 
20077