(VAR x1 )
(RULES 
        1(1(x1)) -> 4(3(x1))
        1(2(x1)) -> 2(1(x1))
        2(2(x1)) -> 1(1(1(x1)))
        3(3(x1)) -> 5(6(x1))
        3(4(x1)) -> 1(1(x1))
        4(4(x1)) -> 3(x1)
        5(5(x1)) -> 6(2(x1))
        5(6(x1)) -> 1(2(x1))
        6(6(x1)) -> 2(1(x1))
        
)