Good day, I have the following data in a worksheet:

2 1 1-Apr-14
2 2 1-Apr-14
3 1 31-Mar-14
3 2 31-Mar-14
3 3 31-Mar-14
3 4 31-Mar-14
3 5 31-Mar-14
3 6 31-Mar-14
4 1 21-Dec-14
5 1 2-Feb-14
6 1 15-Jan-14
6 2 15-Jan-14
7 1 3-Apr-14
8 1 1-Mar-14
9 1 1-Jan-14

I want to count unique numbers in 1st column on a certain month of 3rd column.

Thanks in advance.
Lio.