SUMIF with combined rows

Hi,

I am having a list consisting of two columns. Column A describes a "product" and the currency directly below. In column B i have the quantity of the product and below the value. Now i have products in USD and EUR and would like to only sum up the quantity of all products which are in USD. A simple example is attached and i calculated the target valua manually. The values i would like to sum are market in red. any help highly appreciated. thanks in advance