Sims 2 Missing Letter From Key!?

My manual has the key on it but one of the letters is scratched off! Here is the key: HX?K-XM67-AFLN-YHVY-4HYN. Can anyone help me find out the missing letter/number? Or send me a link to a working keygen or something! Btw, the game is sims 2 double deluxe, I have the manual and the cd case!