How to Show Admob Interstitials on Counted Click? - unity3d

Question

I am trying to something like this:
if button clicked for 4 times, I could show Interstitial?
However i couldn't make it happen.
Created a game object.
Attached script to that object.
Created a restart button.
Implemented this object on that button with onclick-runtime only etc.
Now every time user clicks restart button, interstitial ads show itself. but of course as you might know, it is very annoying.
I dont know how to count how many times users press the restart button and for example show the ads every 3 or 4 times if user press the button.
Thank you.
using UnityEngine;
using System.Collections;
using GoogleMobileAds.Api;
public class AdScript : MonoBehaviour
{
InterstitialAd interstitial;
public string InterstitialId;
// Use this for initialization
void Start()
{
//Request Ads
//RequestBanner();
RequestInterstitial();
}
public void showInterstitialAd()
{
//Show Ad
if (interstitial.IsLoaded())
{
interstitial.Show();
}
}
private void RequestInterstitial()
{
string adUnitId = InterstitialId;
// Initialize an InterstitialAd.
interstitial = new InterstitialAd(adUnitId);
// Create an empty ad request.
AdRequest request = new AdRequest.Builder().Build();
// Load the interstitial with the request.
interstitial.LoadAd(request);
}
}

Answer 1

I can give you idea ,you can use time class to know last showed ad or use variable saying like every 4 game show ad on restart button click.
using UnityEngine;
using System.Collections;
using GoogleMobileAds.Api;
public class AdScript : MonoBehaviou
{
int counter =0;
InterstitialAd interstitial;
public string InterstitialId;
// Use this for initialization
void Start()
{
//Request Ads
//RequestBanner();
RequestInterstitial();
}
public void showInterstitialAd()
{
counter ++;
if(counter%4==0)
{
//Show Ad
if (interstitial.IsLoaded())
{
interstitial.Show();
}
}
}
private void RequestInterstitial()
{
string adUnitId = InterstitialId;
// Initialize an InterstitialAd.
interstitial = new InterstitialAd(adUnitId);
// Create an empty ad request.
AdRequest request = new AdRequest.Builder().Build();
// Load the interstitial with the request.
interstitial.LoadAd(request);
}
}