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

namespace lab_2._1
{
    class Program
    {
        static void Main(string[] args)
        {
            //case1
            int n, sum1, sum = 0;
            Console.WriteLine("Input n");
            n = Convert.ToInt32(Console.ReadLine());
            for(int i = 1; i<=n; i++ )
            {
                sum += (int)Math.Pow(i, 2);
                //Console.WriteLine(sum); uncomment to check iterations
            }
            //case2
            sum1 = (n * (n + 1) * (2 * n + 1)) / 6;

            if(sum==sum1)
            {
                Console.WriteLine("Formule is right");
            }
            else
            {
                Console.WriteLine("Formule isn't right");
            }
        }
    }
}