How can I ignore Negative value in Add Total column in SSRS

I having problem while showing Total Amount. Can some one help how can I exclude negative values in total.I having data as below.Prod Cat --Product -- Year -- Total-------- | -------- ----- -----Cat1 -- Prod1 -- 2014 -- 100Cat1 -- Prod1 -- 2015 -- -50Cat1 -- Prod1 -- 2016 -- 150I want my report to be grouped by Prod Cat, Product. Also want negative total values are not consider as part of column total.If Total is Negative I am hiding that row not to show. But I am seeing that amount is added part of column total.How can I skip that. I am expecting report as this.Prod Cat -- Product -- Year -- Total-------- -------- ----- -----Cat1 -- Prod1 -- 2014 -- 100 ------- Prod1 -- 2016 -- 150------------------------------------- Total: 250