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

namespace Robobit_1
{
    class Program
    {
        static void Main(string[] args)
        {
            double Summa = 0;
            for (double i = 1; i <= 20; i++)
            {
                Summa += Math.Pow(i + 2, 2);
            }
            Console.WriteLine(Summa);
            Console.ReadKey();
        }
    }
}