Identify cells with same values from two columns

In a spreadsheet, I have 2 columns:
Column A contains the name of all the financial documents reports of our company.
Column B contains the name of all the financial documents which my team has worked (these reports can be for both external clients as well as for our company)
Ex:
Col A Col B
F1 F1
F2 F4
F3 F5
F5 F6
F11 F8
e.t.c
My task is to identify all the reports for which my team has worked. From the example, I should be able to extract the following report names: F1, F5

Thanks in advance for all your help.

Note: I am using MS Excell 2007 (Windows Platform)