Stuck with scaling an object

I've been trying to scale an object using its x,y,z axis using a slider. However, I have a problem trying to use 3 different sliders for each axis (x for length, y for width, and z for height). The problem is that only one slider works (which the only thing that scales is the height) in the code that I've done even though I've declared 3 sliders to perform a transform function for each axis. Can someone please tell me what's wrong and how to debug something like this? I've very new in unity. Thanks :)

Here's the code that I used on my sliders

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class ScaleSlider : MonoBehaviour {
 
     public Slider sliderLength;
     public Slider sliderWidth;
     public Slider sliderHeight;
 
     // Use this for initialization
     void Start () {
         sliderLength.value = 1;
         sliderWidth.value = 1;
         sliderHeight.value = 1;
 
     }
 
     // Update is called once per frame
     void Update () {
         transform.localScale = new Vector3 (sliderLength.value*1f, 1, 1);
         transform.localScale = new Vector3 (1, sliderWidth.value*1f, 1);
         transform.localScale = new Vector3 (1, 1, sliderHeight.value*1f);
     }
 }