Character cannot move up the stairs and only slide down

Hi, guys. I have a problem with moving my character up and down the slopes.

I have a Polygon Collider 2D on stairs and when I move my character up he is not moving but just sliding down.

How can I make my character go up the slope and stop him from sliding down?

Character has Capsule Collider 2D and Rigidbody2D. Also I’m using Input-System.