(VAR X Y Z )
(RULES 
        __(__(X, Y), Z) -> __(X, __(Y, Z))
        __(X, nil) -> X
        __(nil, X) -> X
        U11(tt) -> tt
        U21(tt) -> U22(isList)
        U22(tt) -> tt
        U31(tt) -> tt
        U41(tt) -> U42(isNeList)
        U42(tt) -> tt
        U51(tt) -> U52(isList)
        U52(tt) -> tt
        U61(tt) -> tt
        U71(tt) -> U72(isPal)
        U72(tt) -> tt
        U81(tt) -> tt
        isList -> U11(isNeList)
        isList -> tt
        isList -> U21(isList)
        isNeList -> U31(isQid)
        isNeList -> U41(isList)
        isNeList -> U51(isNeList)
        isNePal -> U61(isQid)
        isNePal -> U71(isQid)
        isPal -> U81(isNePal)
        isPal -> tt
        isQid -> tt
        
)