using System;

public class Program

{

    public static void Main()

    {

          Console.Write("Enter the nth number of the Fibonacci Series: ");

            int number = Convert.ToInt32(Console.ReadLine());

            number = number - 1;

           Console.Write(NthFNumber(number));

            Console.ReadKey();

    }

            public static int NthFNumber(int n)

        {

            if ((n == 0) || (n == 1))

            {

                return n;

            }

            else

            {

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

            }

        }

}