namespace UnityStandardAssets.Characters.FirstPerson

I can't get any script component from other object. I got this error:

error CS0246: The type or namespace name `MyScript' could not be found. Are you missing a using directive or an assembly reference?

I'm using default FirstPersonController.cs.

 namespace UnityStandardAssets.Characters.FirstPerson
     {
         [RequireComponent(typeof (CharacterController))]
         [RequireComponent(typeof (AudioSource))]
         public class FirstPersonController : MonoBehaviour
         {
             private GameObject ObjController;
             private void Start()
             {
                ObjController = GameObject.Find("ObjController");
                float MyVar = ObjController.GetComponent<MyScript>().MyVarf;

             }
         }
     }