(VAR k l x y z )
(STRATEGY INNERMOST)
(RULES 
        a(h,h,h,x) -> s(x)
        a(l,x,s(y),h) -> a(l,x,y,s(h))
        a(l,x,s(y),s(z)) -> a(l,x,y,a(l,x,s(y),z))
        a(l,s(x),h,z) -> a(l,x,z,z)
        a(s(l),h,h,z) -> a(l,z,h,z)
        +(x,h) -> x
        +(h,x) -> x
        +(s(x),s(y)) -> s(s(+(x,y)))
        +(+(x,y),z) -> +(x,+(y,z))
        s(h) -> 1
        app(nil,k) -> k
        app(l,nil) -> l
        app(cons(x,l),k) -> cons(x,app(l,k))
        sum(cons(x,nil)) -> cons(x,nil)
        sum(cons(x,cons(y,l))) -> sum(cons(a(x,y,h,h),l))
        
)