How do I use Pivot Tables to find missing values? I know how to do this with a Union Query in Access, but not in Excel. Suppose I have the following data:

I, J, Result
1,1,5
1,2,6
1,3,7
1,4,8
1,5,9
2,1,10
2,2,11
2,3,12

I want to return: I,J = 2,4 and 2,5 because there are no results for those I,J.

How to do? Thanks!