using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {

        static int Fib(int n)
        {
            int s = 0;
            if (n == 1 || n == 2) return s = 1;
            else return s = Fib(n - 1) + Fib(n - 2);
        }

        static int NWD(int a, int b)
        {
            if (b == 0) return a;
            else return NWD(b, a % b);
        }

        static int Aryt(int a1, int r, int n)
        {
            if (n == 1) return a1;
            else return Aryt(a1, r, (n - 1))+r;
        }

        static int Geo(int a1, int r, int n)
        {
            if (n == 1) return a1;
            else return Aryt(a1, r, n) * r;
        }

        static void Main(string[] args)
        {
            int a1,r,n;
            Console.Write("Podaj a1: ");
            a1 = Int32.Parse(Console.ReadLine());
            Console.Write("Podaj r: ");
            r = Int32.Parse(Console.ReadLine());
            Console.Write("Podaj n: ");
            n = Int32.Parse(Console.ReadLine());
            Console.WriteLine("a1 {0} r {1} n {2} w {3}", a1, r, n, Geo(a1,r,n));
            Console.ReadKey();
        }
    }
}