void Start()
    {
        // Setup UI
        RewardedVideoButtonTitle      = GameObject.Find("RewardedVideoButtonTitle").GetComponent <Text> ();
        RewardedVideoButtonTitle.text = REWARDED_VIDEO_BUTTON_TITLE_PRELOAD;
        StatusText      = GameObject.Find("StatusText").GetComponent <Text> ();
        StatusText.text = "";

        // Check if user replaced the SDK key
        if ("YOUR_SDK_KEY_HERE".Equals(SDK_KEY))
        {
            StatusText.text = "ERROR: PLEASE UPDATE YOUR SDK KEY IN Assets/MainMenu.cs";
        }
        else
        {
            // Set SDK key and initialize SDK
            AppLovin.SetSdkKey(SDK_KEY);
            AppLovin.InitializeSdk();
            AppLovin.SetUnityAdListener("MainMenu");
            AppLovin.SetRewardedVideoUsername("demo_user");
        }
    }