using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace AtCoder.B
{
    internal static class CR
    {
        public static string GetText() { return Console.ReadLine(); }
        public static List<string> GetTexts() { return Console.ReadLine().Split(' ').ToList(); }
        public static long GetLong() { return long.Parse(Console.ReadLine()); }
        public static List<long> GetLongs() { return Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToList(); }
    }

    public class Program
    {
        public static long N { get; private set; }

        public static void Main() { var r = GetResult(); Debug.WriteLine(r); Console.Write(r); }

        private static object GetResult()
        {
            N = CR.GetLong();

            var sum = 0L;
            for (long i = 0; i <= N; i++)
            {
                if (i % 3 != 0 && i % 5 != 0)
                {
                    sum += i;
                }
            }

            return sum;
        }
    }
}
