---

using System;

class Program
{
    static void Main()
    {
        Console.Write("Введите n: ");
        int n = int.Parse(Console.ReadLine());

        int y = 0;

        for (int i = 1; i <= n; i++)
        {
            y += (2 * i + 1);
        }

        Console.WriteLine("y = " + y);
    }
}