(VAR X Y )
(RULES 
        f(X) -> if(X, c, n__f(n__true))
        if(true, X, Y) -> X
        if(false, X, Y) -> activate(Y)
        f(X) -> n__f(X)
        true -> n__true
        activate(n__f(X)) -> f(activate(X))
        activate(n__true) -> true
        activate(X) -> X
        
)