Solved: Cell Color change Vlookup

[Emoncada]

I have a range from G3:G37 with Serial Numbers.
I want the user to enter his serial numbers down column A.

If a value that is entered in column A matches a value in the G3:G37 Range i would like that cell to turn red.

How can I make this happen. Thanks.

[Emoncada]

I figured it out using Conditional Formatting.
Using the following Formula.
=COUNTIF($G$3:$G$37,A3)