Pr5R4ex1

using System;

namespace test
{
    class Program
    {
        static int Func (int a, int b, int i, int n)
        {
            if (n == 1)
                return a;
            if (n == 2)
                return b;
            int new_a = Math.Abs (a) - 6 * b;
            if (i < n - 2)
                return Func (new_a, a, i++, n);
            else
                return new_a;
        }
        static void Main ()
        {
            Console.WriteLine ("Enter n ");

            int n = int.Parse (Console.ReadLine ());

            int res = Func (-10, 2, 1, n);
            Console.WriteLine ("Result = {0} ", res);
        }
    }
}