using System;

public class Program

{

    public static void Main()

    {

        int X = TinhTong();

        Console.WriteLine(X);

    }

        static int TinhTong()

        {

            int[] A = new int [ 20 ];

            int count = 0;

            int tong = 0;

            for (int i = 1; i < 60; ++i)

            {

                if (count < 20)

                {

                    if (i % 3 == 0)

                    {

                          A[count] = i;

                          count+=1;

                    }

                     else if (i % 5 == 0)

                     {

                          A[count] = i;

                          count+=1;

                     }

                }

            }

            for (int i  = 0; i < 20; ++i)

            {

                tong = tong + A[i];

            }

            return tong;

        }

}