Facebook c# sdk - How to know if the user is using the app for the first time

I'm trying to know if a user uses the Facebook App for his first time. Is there any information on cookie returned about it, or do i have to create a database 开发者_如何学Cand store the users ids for example?

Thanks

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Facebook does not provide this information for you (nor does the C# SDK). You will have to track this yourself in a database or something.