Sum square difference №6

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

//The sum of the squares of the first ten natural numbers is,

//12 + 22 + ... + 102 = 385
//The square of the sum of the first ten natural numbers is,

//(1 + 2 + ... + 10)2 = 552 = 3025
//Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.

//Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

namespace 6
{
    class Program
    {
        static void Main(string[] args)
        {
            long sum = 0;
            for (int i = 1; i < 101; i++) sum += i * i;
            Console.WriteLine(- sum + 101 * 101 * 2500);
        }
    }
}