im having trouble changing wich joystick is set to wich axis

i cant change wich joystick is being used , in the input manager when i change the value of joy mum from joystick 1 to 2 or 3 nothing happens and the axis being returned remains the same instead of changing to another joystick

i am using this simple script to return the value of an axis

               using UnityEngine;

using System.Collections;

public class test : MonoBehaviour {

// Update is called once per frame
void Update () {Debug.Log(
    Input.GetAxis("Horizontal")
    );

}

}

i use a ps2 to usb plug and a ps2 controler but even if that was the problem it should return nothing when i change the axis to joystick 2 instead of remaining the same

,am i doing something wrong ?

have you checked the input settings under the edit tab? how are your inputs being read from the controller?