how can i fix it i want to disabled FirsPersonController when my healthvalue<=0 but it haveProblem T-Tsry for my bad english skill

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI; using UnityStandardAssets.Characters.FirstPerson;

public class HealthSystem : MonoBehaviour { public float health = 100f; public float healthMax = 100f; public Slider healthSlider; public GameObject failPanel; public GameObject player; void Awake () {

     player = this.gameObject;
     player.GetComponent<FirstPersonController>();
 }

 void Start()
 {
     health = healthMax;
     healthSlider.GetComponent<Slider>().maxValue = healthMax;
     healthSlider.GetComponent<Slider>().value = health;
 }

 // Update is called once per frame
 void Update()
 {
     healthSlider.GetComponent<Slider>().value = health;
     if (healthSlider.value <= 0)
     {
         failPanel.SetActive(true);
         player.GetComponent<FirstPersonController>().enabled = false;
         Cursor.visible = true;
     }
 }