Excel IF functions and equations

I have a problem in excel, I want to make mathematical equation, ive tried it and I have problem with that function, it gives me error. I want have result in G6 if i type W in F6, then it will type in G6 : E6 if i type L in F6, then it will type in G6 : -D6 i think that I can get -D6 by multiplying D6 with -1

link on picture :Link

by the way : KDYŽ means IF in my language