How do i fix error CS0246

Dose anyone know how to fix this script

Pic of error: https://gyazo.com/1ced2f3adf2a34620396bc0da37e0df9

using UnityEngine;
using System.Collections;
//Used for fading out the screen
using UnityEngine.UI;
//Using for modifying motion blur on camera
using UnityStandardAssets.ImageEffects;

public class FlashbangEffectScript : MonoBehaviour {

//Used to toggle the effect
public bool isBlinded = false;
bool routineStarted;

[Header("Settings")]

//How long before the effect can be enabled again
public float effectTimer = 10.0f;

//How fast the alpha fades out
public float alphaTransitionMultiplier = 0.15f;
//Alpha value
float imageAlphaValue;

//How fast the blur fades out
public float blurTransitionMultiplier = 0.05f;
//Motion blur value
float motionBlurValue;

[Header("Components")]

//Main camera, attached to the prefab
public Camera effectCamera;
//Audio source
public AudioSource flashbangAudio;
//Flashbang image screen effect
public CanvasGroup flashbangImage;

void Start () {

//Make sure flashbang image is not showing at start
flashbangImage.alpha = 0;

//Make sure motion blur is off at start
effectCamera.GetComponent<MotionBlur>().blurAmount = 0;

//Make sure audio reverb zone is off at start
effectCamera.GetComponent<AudioReverbZone>().enabled = false;
}

void Update () {

//Set the motion blur value
effectCamera.GetComponent<MotionBlur> ().blurAmount = motionBlurValue;
//Set the image alpha value
flashbangImage.alpha = imageAlphaValue;

//Decrease the motion blur value over time * multiplier
motionBlurValue -= Time.deltaTime * blurTransitionMultiplier;
//Decrease the image alpha value over time * multiplier
imageAlphaValue -= Time.deltaTime * alphaTransitionMultiplier;

//If blinded is true
if (isBlinded == true) {
if (routineStarted == false) {

//Start the flashbang effect timer
StartCoroutine(FlashbangEffect());

routineStarted = true;
}
}

//Make sure motion blur value
//is not negative value
if (motionBlurValue < 0) {
motionBlurValue = 0;
}

//Make sure image alpha value
//is not a negative value
if (imageAlphaValue < 0) {
imageAlphaValue = 0;
}
}

//Start flashbang effect
IEnumerator FlashbangEffect () {

//Play audio effect
flashbangAudio.Play();
//Enable motion blur effect
motionBlurValue = 0.92f;
//Make flashbang image visible
imageAlphaValue = 1.0f;
//Enable audio reverb zone
effectCamera.GetComponent<AudioReverbZone>().enabled = true;
//Wait for set amount of time
yield return new WaitForSeconds (effectTimer);

isBlinded = false;
routineStarted = false;

//Disable audio reverb zone
//after set amount of time
effectCamera.GetComponent<AudioReverbZone>().enabled = false;

}
}

 

Can you please edit your post and put the code inside code-tags:
https://forum.unity.com/threads/using-code-tags-properly.143875/

 

Have you imported the package (UnityStandardAssets) into your project?