using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Fib(7));

        allFib();

    }

​

    public static int Fib(int n)

    {

        if (n <= 2)

            return 1;

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

    }

​

    public static int allFib()

    {

        int num = 0;

        int numTwo = 1;

        int ans = 0;

        for (int i = 0; i <= 20; i++)

        {

            if (i <= 1)

            {

                ans = i;

            }

            else

            {

                ans = num + numTwo;

                num = numTwo;

                numTwo = ans;

            }

            Console.WriteLine(ans);

        }

​

        return ans;

    }

}