public class MainActivity extends AppCompatActivity {

    private InterstitialAd mInterstitialAd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Sample AdMob app ID: ca-app-pub-3940256099942544~3347511713
        MobileAds.initialize(this, "ca-app-pub-4317187826403980~1326261366");

        mInterstitialAd = new InterstitialAd(this);
        mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");
        mInterstitialAd.loadAd(new AdRequest.Builder().build());

    }