Countif to to choose number of items?

Hi

I have attached my example.

Is there a simpler formula I can use that combines IF and COUNT functions. CountIf, maybe?

I have, let's say, 17 items and I want to choose 5 items out of them. Each time I pick one I am told how many I have chosen. When I reach 5, I am told that I have chosen too many.

Thanks

Patish