The name `EventSystems' does not exist in the current context

The questions in the title, I made sure that I added this:
using UnityEngine.EventSystems;
right under:

   using UnityEngine;
   using System.Collections;

So I’m a bit dumbfounded, anyway this is my code:

public GameObject currentSelectedGameObject;

void Update () {
		if (Input.GetMouseButtonDown (0)) {
		if (!EventSystems.EventSystem.currentSelectedGameObject ()) {
					Vector3 mousePosition = Input.mousePosition;
					mousePosition.z = 10; // distance from the camera
					target = Camera.main.ScreenToWorldPoint (mousePosition);
					target.z = transform.position.z;
		transform.position = Vector3.MoveTowards (transform.position, target, speed * Time.fixedDeltaTime);

just add Using UnityEngine.EventSystems

Please help me, even putting that “using”, i have the same error… i dont know what to do…