Another Sumif equivalent

Hello

We have a a database that we are trying to sum across. 

We have a report that shows multiple report numbers and number of days open. 

All reports start with an "A" designator. Each time a report is reopened, it gets a subsequent Alpha designator, "B", "C", etc. 

We need to calculate the total time the report is open despite the number of times it has been reopened. 

I understand how to do this in excel with SumIF, but we cannot get this to work in PowerBI. 

I would appreciate some direction on how this is done.