(VAR x1 )
(RULES 
        a12(a12(a12(a12(x1)))) -> x1
        a13(a13(a13(a13(x1)))) -> x1
        a14(a14(a14(a14(x1)))) -> x1
        a15(a15(a15(a15(x1)))) -> x1
        a16(a16(a16(a16(x1)))) -> x1
        a23(a23(a23(a23(x1)))) -> x1
        a24(a24(a24(a24(x1)))) -> x1
        a25(a25(a25(a25(x1)))) -> x1
        a26(a26(a26(a26(x1)))) -> x1
        a34(a34(a34(a34(x1)))) -> x1
        a35(a35(a35(a35(x1)))) -> x1
        a36(a36(a36(a36(x1)))) -> x1
        a45(a45(a45(a45(x1)))) -> x1
        a46(a46(a46(a46(x1)))) -> x1
        a56(a56(a56(a56(x1)))) -> x1
        a13(a13(x1)) -> a12(a12(a23(a23(a12(a12(x1))))))
        a14(a14(x1)) -> a12(a12(a23(a23(a34(a34(a23(a23(a12(a12(x1))))))))))
        a15(a15(x1)) -> a12(a12(a23(a23(a34(a34(a45(a45(a34(a34(a23(a23(a12(a12(x1))))))))))))))
        a16(a16(x1)) -> a12(a12(a23(a23(a34(a34(a45(a45(a56(a56(a45(a45(a34(a34(a23(a23(a12(a12(x1))))))))))))))))))
        a24(a24(x1)) -> a23(a23(a34(a34(a23(a23(x1))))))
        a25(a25(x1)) -> a23(a23(a34(a34(a45(a45(a34(a34(a23(a23(x1))))))))))
        a26(a26(x1)) -> a23(a23(a34(a34(a45(a45(a56(a56(a45(a45(a34(a34(a23(a23(x1))))))))))))))
        a35(a35(x1)) -> a34(a34(a45(a45(a34(a34(x1))))))
        a36(a36(x1)) -> a34(a34(a45(a45(a56(a56(a45(a45(a34(a34(x1))))))))))
        a46(a46(x1)) -> a45(a45(a56(a56(a45(a45(x1))))))
        a12(a12(a23(a23(a12(a12(a23(a23(a12(a12(a23(a23(x1)))))))))))) -> x1
        a23(a23(a34(a34(a23(a23(a34(a34(a23(a23(a34(a34(x1)))))))))))) -> x1
        a34(a34(a45(a45(a34(a34(a45(a45(a34(a34(a45(a45(x1)))))))))))) -> x1
        a45(a45(a56(a56(a45(a45(a56(a56(a45(a45(a56(a56(x1)))))))))))) -> x1
        a12(a12(a34(a34(x1)))) -> a34(a34(a12(a12(x1))))
        a12(a12(a45(a45(x1)))) -> a45(a45(a12(a12(x1))))
        a12(a12(a56(a56(x1)))) -> a56(a56(a12(a12(x1))))
        a23(a23(a45(a45(x1)))) -> a45(a45(a23(a23(x1))))
        a23(a23(a56(a56(x1)))) -> a56(a56(a23(a23(x1))))
        a34(a34(a56(a56(x1)))) -> a56(a56(a34(a34(x1))))
        
)