How to read a Variable an use it within a Function

[Gagamel]

Hi, i have the following problem, how can i read a Variable, taht i want to use within a also readed function.
example:
func(F,Y):- read(X),number(X),Y is F.
should yield to:
func(X+1,Y). with |:3 readed Y=4.
Thx for your help