Combining two sets of data

I have two sets of data that I need to combine. In this example, I have data in G4, G6, G8, G10 and G12, i.e. in every two rows. I also have data in F5, F7, F9 and F11. How can I quickly move the data from the F column to the empty cells of G5, G7, G9 and G11. Attached is the Excel file with the situation.

Thank you for your help.