using System;

public class Program

{

    public static int summ = 0;

    public static void Main()

    {

​

        F(4);

        Console.WriteLine("summ={0}", summ);

    }

    static void Add(int i)

    {

        Console.WriteLine(i);

        summ += i;

    }

    static void  F(int n)

    {

       Console.WriteLine("f({0})", n);

​

        Add(2*n+1); 

        if (n > 1)

        {

                Add(3*n-8);

            F(n-1);

            F(n-4);

        }

        Console.WriteLine(string.Format("exit n = {0} summ={1}", n, summ));

    }

}