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: 7993 sottrazione 9845 aggiunta 8690 sottrazione 815 aggiunta 9984 sottrazione 9881 aggiunta 8344 sottrazione 4685 aggiunta 8779
A: 
18564