using System;

public class Program

{

    public static void Main()

    {

        int userInput = 10;

        int fibNumber = Fib(userInput);

        Console.WriteLine(fibNumber);

    }

    static int Fib(int n)

    {

        if (n<=1)

            return n;

        return Fib(n-1) + Fib(n-2);

    }

}