Error unity error CS0200: Property or indexer `UnityStandardAssets.Characters.FirstPerson.RigidbodyFirstPersonController.Running' cannot be assigned to (it is read only)

public class PlayerController : MonoBehaviour {

 public float playerHealth = 100f, maxPlayerHealth = 100f, playerStrength = 100f, maxPlayerStrength = 100f, playerHungry = 100f, maxPlayerHungry = 100f, playerThirst = 100f, maxPlayerThirst = 100f;
 public bool cantRunWithoutStrength = true;
 public float healthRegeneration = 0.1f, strengthRegeneration = 0.1f, hungryDownspeed = 0.001f, thirstDownspeed = 0.001f, runExpensOfStrength = 0.04f, hungryDamagePerSec = 0.25f, thirstDamagePerSecond = 0.15f;
 public Image hpBar, strBar, hungBar, thirBar;
 RigidbodyFirstPersonController fpc;
 float maxBarLength = 256f;
 float lastHPTimer = 0f, lastHUNGTimer = 0f, lastTHIRTimer = 0f, lastTHIRSTDamage = 0f, lastHUNGRYDamage = 0f;

 void Start()
 {
     fpc = gameObject.GetComponent<RigidbodyFirstPersonController>();
     UpdateBars();
     maxBarLength = hpBar.rectTransform.sizeDelta.x;
 }

 public void ShowPlayerInfo(bool show)
 {
     hpBar.transform.parent.parent.gameObject.SetActive(show);
 }

 void Update()
 {
     if (!fpc.Running)
     {
         playerStrength -= runExpensOfStrength;
         playerStrength = Mathf.Clamp(playerStrength, 0, maxPlayerStrength);
         UpdStrength();
     }

     if (cantRunWithoutStrength)
     {
         if (playerStrength < 10f)
         {
             fpc.Running = false;
         }
         else
         {
             fpc.Running = true;
         }
     }