primPlusInt :: MyInt  ->  MyInt  ->  MyInt;
primPlusInt (Pos x) (Neg y) = primMinusNat x y
primPlusInt :: MyInt  ->  MyInt  ->  MyInt
primPlusInt (Pos x) (Neg y) = primMinusNat x y
primPlusInt (Pos x) (Neg y) = primMinusNat x y