# Excel: Calculate Unique Circulation with a Single Formula (sum unique records)

I have some data which looks like this: Excel 2010

A B C
1 Media Date Circulation
2 Newspaper_01 1/01/2014 1000
3 Newspaper_02 2/01/2014 1000
4 Newspaper_02 2/01/2014 1000
5 Newspaper_02 3/01/2014 1000
6 Newspaper_03 5/01/2014 1000
The sum of circulation values above is 5000. The unique circulation is 4000. Notice that Newspaper_02 appears on three three rows, but the second row does not count because it has the same date (each row represents a newspaper article, on January 2nd Newspaper_02 had two articles. The circulation for the second article does not count because it occurred in the same issue as the first article. I want to calculate the unique circulation with a single formula, if this is possible. If it is not possible I have other ways, but I would like to find out if there is a way of doing with a single formula. Do any of you Excel geniuses out there see a way that this might be achieved? I would greatly appreciate any help with this. Cheers.