Using UnityStandardAssets.CrossPlatformInput;

when im using using UnityStandardAssets.CrossPlatformInput; im getting this error, Assets\BallController.cs(3,7): error CS0246: The type or namespace name 'UnityStandardAssets' could not be found (are you missing a using directive or an assembly reference?)
I don’t have standard assets installed because it says the got removed or something but im following a course and im stuck pls help
here is the begining of my code:

using System.Collections;
using System.Collections.Generic;
using UnityStandardAssets;
using UnityEngine;

pls help
thanks.