drop n c :=
    n
        zero := c
        odd n := drop n c
        even n := drop n c

copy n c :=
    n
        zero := 
            n1 = _ c:= c.zero
            n2 = _ c:= c.zero
            c n1 n2
        odd n :=
            copy n -> n1 n2
            n1 = _ c:= c.odd n1
            n2 = _ c:= c.odd n2
            c n1 n2
        even n :=
            copy n -> n1 n2
            n1 = _ c:= c.even n1
            n2 = _ c:= c.even n2
            c n1 n2

inc_v n c :=
    n
        zero := 
            n = _ c:= c.zero
            n = _ c:= c.odd n
            c n
        odd n :=
            n = _ c:= c.even n
            c n
        even n :=
            inc n -> n
            n = _ c:= c.odd n
            c n

inc_n n c :=
    n
        zero :=
            n = _ c:= c.zero
            c.odd n
        odd n :=
            c.even n
        even n :=
            n = inv_v n
            c.odd n        

test_add c m n :=
    from m -> m
    from n -> n
    add m n -> m
    count c m

add_v m n c :=
    m 
        zero := c n
        odd m :=
            n
                zero := 
                    m = _ c:= c.odd m
                    c m
                odd n :=
                    add m n -> m
                    m = _ c:= c.even m
                    c m
                even n :=
                    add m n -> m
                    inc m -> m
                    m = _ c:= c.odd m
                    c m
        even m :=
            n
                zero := 
                    m = _ c:= c.odd m
                    c m
                odd n :=
                    add m n -> m
                    inc m -> m
                    m = _ c:= c.odd m
                    c m
                even n :=
                    add m n -> m
                    inc m -> m
                    m = _ c:= c.even m
                    c m

add_n m n c :=
    m 
        zero := n c
        odd m :=
            n
                zero := 
                    c.odd m
                odd n :=
                    add m n -> m
                    c.even m
                even n :=
                    add m n -> m
                    inc m -> m
                    c.odd m
        even m :=
            n
                zero := 
                    c.even m
                odd n :=
                    add m n -> m
                    inc m -> m
                    c.odd m
                even n :=
                    add m n -> m
                    inc m -> m
                    c.even m

double_n m c :=
    m
        zero := c.zero
        odd n := 
            n = time_2_n n
            c.even n
        even n :=
            n = _ c := c.odd n
            c.even n

mul_n m n c :=
    m
        zero := c.zero
        odd m :=
            copy m -> m1, m2
            n = mul_n n m1
            n = double_n n
            add_n n m2 c
        even m :=
            copy m -> m1 m2
            n = mul_n n m1
            n = add_n m n
            n = double_n n c