using System;

public class Program

{

    public static void Main()

    {

        var sum = 0;

        for(int i = 0; i <1000; i++) 

        {

            if(i % 3 == 0 || i % 5 == 0 ) 

            {

                sum += i;

            }   

        }

        Console.WriteLine(sum);

    }

}