(VAR x y z )
(RULES 
        +(0,0) -> 0
        +(0,1) -> 1
        +(0,2) -> 2
        +(0,3) -> 3
        +(0,4) -> 4
        +(0,5) -> 5
        +(0,6) -> 6
        +(0,7) -> 7
        +(0,8) -> 8
        +(0,9) -> 9
        +(1,0) -> 1
        +(1,1) -> 2
        +(1,2) -> 3
        +(1,3) -> 4
        +(1,4) -> 5
        +(1,5) -> 6
        +(1,6) -> 7
        +(1,7) -> 8
        +(1,8) -> 9
        +(1,9) -> c(1,0)
        +(2,0) -> 2
        +(2,1) -> 3
        +(2,2) -> 4
        +(2,3) -> 5
        +(2,4) -> 6
        +(2,5) -> 7
        +(2,6) -> 8
        +(2,7) -> 9
        +(2,8) -> c(1,0)
        +(2,9) -> c(1,1)
        +(3,0) -> 3
        +(3,1) -> 4
        +(3,2) -> 5
        +(3,3) -> 6
        +(3,4) -> 7
        +(3,5) -> 8
        +(3,6) -> 9
        +(3,7) -> c(1,0)
        +(3,8) -> c(1,1)
        +(3,9) -> c(1,2)
        +(4,0) -> 4
        +(4,1) -> 5
        +(4,2) -> 6
        +(4,3) -> 7
        +(4,4) -> 8
        +(4,5) -> 9
        +(4,6) -> c(1,0)
        +(4,7) -> c(1,1)
        +(4,8) -> c(1,2)
        +(4,9) -> c(1,3)
        +(5,0) -> 5
        +(5,1) -> 6
        +(5,2) -> 7
        +(5,3) -> 8
        +(5,4) -> 9
        +(5,5) -> c(1,0)
        +(5,6) -> c(1,1)
        +(5,7) -> c(1,2)
        +(5,8) -> c(1,3)
        +(5,9) -> c(1,4)
        +(6,0) -> 6
        +(6,1) -> 7
        +(6,2) -> 8
        +(6,3) -> 9
        +(6,4) -> c(1,0)
        +(6,5) -> c(1,1)
        +(6,6) -> c(1,2)
        +(6,7) -> c(1,3)
        +(6,8) -> c(1,4)
        +(6,9) -> c(1,5)
        +(7,0) -> 7
        +(7,1) -> 8
        +(7,2) -> 9
        +(7,3) -> c(1,0)
        +(7,4) -> c(1,1)
        +(7,5) -> c(1,2)
        +(7,6) -> c(1,3)
        +(7,7) -> c(1,4)
        +(7,8) -> c(1,5)
        +(7,9) -> c(1,6)
        +(8,0) -> 8
        +(8,1) -> 9
        +(8,2) -> c(1,0)
        +(8,3) -> c(1,1)
        +(8,4) -> c(1,2)
        +(8,5) -> c(1,3)
        +(8,6) -> c(1,4)
        +(8,7) -> c(1,5)
        +(8,8) -> c(1,6)
        +(8,9) -> c(1,7)
        +(9,0) -> 9
        +(9,1) -> c(1,0)
        +(9,2) -> c(1,1)
        +(9,3) -> c(1,2)
        +(9,4) -> c(1,3)
        +(9,5) -> c(1,4)
        +(9,6) -> c(1,5)
        +(9,7) -> c(1,6)
        +(9,8) -> c(1,7)
        +(9,9) -> c(1,8)
        +(x,c(y,z)) -> c(y,+(x,z))
        +(c(x,y),z) -> c(x,+(y,z))
        c(0,x) -> x
        c(x,c(y,z)) -> c(+(x,y),z)
        
)