Summing with Duplicates

Hi,

In columns A:C I have sales data for 2 regions as well as the product names associated with the region and would like in cell F1 to create a formula to sum the regional sales.

The wrinkle is that because the data is arranged by product, there is duplication of regional sales values. E.g. UK is represented twice so simply summing the values in column C associated with UK will double-count the 200.

I can't simply filter out unique values in column C because if I were to add, for example, North America to the sample data which also had sales of 200, then that would not be counted.

Can someone please suggest a solution?

Thanks!