I want to perform a vlookup with an if statement inside. I currently have 

`=LOOKUP("Metallic Gold Flash Tattoo Arabic",A:A,IF(INDIRECT(ADDRESS(ROW(), E)))<0,INDIRECT(ADDRESS(ROW(), C)),0)`

I want to sum up all the units of that product type in column A, however I only want to sum up the ones that have been sold and not bought. Column C is units and E is price. Sold are positive and negative are bought.

I am using Google Sheets.