if (Input.GetKeyDown(KeyCode.LeftArrow)) {
            speed = -speedX;
            }
        if (Input.GetKeyUp(KeyCode.LeftArrow)) {
            speed = 0;
            }
      //run

        if (Input.GetKeyDown(KeyCode.LeftShift)) {
            speed *= runSpeed;
            run = true;
            }
        if (Input.GetKeyUp(KeyCode.LeftShift)) {
            speed /= runSpeed;
            run = false;
            }