So no matter what we do, we're going to have to pay that 20 just from the get-go and then we're going to pay $8/session so it's going to be $20 + ($8 x # of Sessions) so that's interesting and you can see if you put S is 0 here, if you make S = 0 you get 20 + (8 x 0) which is 20 if you say S is 1, you get 20 + (8 x 1) which is 28 so you see that each of these S's and C's they satisfy this equation 