Problem with my Player move click

Guys, I have a question on player move click. I have my player move click on my right click which is comfortable for me. I use my player attack move with A. But the problem is when I click on my right click trying to move my champion in a team fight, sometimes I misclick somewhere so that my champion will attack the target that my right click had chosen. My question is how to set the player move click only on movements so that I would not attack any target if my mouse MB2 has clicked on a target accidentally that my champion will start attacking it. The only attack target key I want is A, I do not wish that my right click can also attack targets.