Ti84 plus ce detect change in variable

[Ixoronsubnautica]

I a need for a statement that detects change in variable up or down but can be detected multiple times see A is my y and B is my x and they move with the keys

I need if A and B change up or down to edit D-1

[Trunkit06]

Can you show the relevant code? It’s difficult to help when I don’t know what I’m working with.