Cell To Automatically Populate

i am working on a spreadsheet that includes a large amount of statistical numbers / records. one part includes a win / loss column and the very next column i am entering the final score for each game. to max this easier to comprehend, there are only 3 columns. 1st column lists my opponent, the 2nd lists, with just a red L for loss, or a green W for win, and the 3rd column has the final score. (my score is always first, regardless of whether i won or lost the game.)

OPP F SCORE
--------------------------------------------------
John W 23-10
Paul L 17-25
Terri W 10-7

This is what i'm searching for: (and the easiest way possible b/c i'm not familiar with macros / visual basic, etc.) ... Once i enter the score: ##-##, I would like the "F" (final outcome) cell to automatically populate either a bold red L for a loss, or a bold green W for a win. My scores are almost never 3 digits, so they would almost always be ##-##. if u need me to provide more info,