using System;

public class Program

{

public static int sum(int n)

{

    int sum=0;

        for(int i=1;i<=10;i++)

            sum+=(i*i);

        return (n*(n+1)*(2*n+1))/6;

}

    public static void Main()

    {

        int n=10;

        Console.WriteLine("The sum of the first ten natural numbers is:");

        Console.WriteLine(sum(n));

    }

}