Show an ad once every 2 times

An advertisement from admob shows in my android app every time the user loses. However I want it to appear after the loss once every 2 loses. E.g i died and the ad showed the next time i died it didnt show after that it showed and so on. It takes a gap and then shows again after.

     //Setting up the ad
    InterstitialAd interstitial;
    	private void RequestInterstitial()
    	{
    		#if UNITY_ANDROID
    		string adUnitId = "ca-app-pub-5920324855307233/4763839506";

    		#elif UNITY_IPHONE
        		string adUnitId = "ca-app-pub-5920324855307233/4763839506";
        		#else
        		string adUnitId = "unexpected_platform";
        		#endif
        		
        		// 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);
        	}

	void Start(){
		RequestInterstitial();
	}

void Update(){
    if (interstitial.IsLoaded()) {
    	interstitial.Show();
    	 }
     }

Something like this should solve your issue

void Start(){

  PlayerPrefs.SetInt("ShouldShowAd", 0);
}

void ShowAd(){
 if(PlayerPrefs.GetInt("ShouldShowAd") == 0)
  {
       PlayerPrefs.SetInt("ShouldShowAd", 1);
        // do nothing and don't show ad
  }
else
  {
      PlayerPrefs.SetInt("ShouldShowAd", 0);
      // show ad here
  }
}

// call show ad upon player death

My suggestion would be to do it like this (the method I use myself).

Player dies

Check interstitial is ready

If it is then show it (but don’t request another)

If it isn’t then request an interstitial (but don’t show it.)

Rinse and repeat

This results in an interstitial being shown every two deaths, with no need for counters, playerprefs saving etc. etc.