How to add particular values sum in a column

[Anonymous]

Hi friends good day 2 all ,I'm having an issue with expressiopns sum.

Item is a column consists of values as A,B,C,D,E,Class.In pivot table taking dimension as Item and measures as peril,renewal .while sum it up the dimension Item we need  to sum only(A+B+C+D+E) and not include Class in sum(exclude).can any one help on this to do in set analysis to exclude one value in a column..

[tresesco]

Sum({<Item-={'Class'}>}measure)            // Note '-' sign before '='