using System; using System.Linq; using System.Collections.Generic; class Program { /// /// プログラムのエントリポイント /// /// static void Main(string[] args) { long max = long.Parse(Console.ReadLine()); var list = new List(); for (long i = 3; i <= max; i += 3) list.Add(i); for (long i = 5; i <= max; i += 5) list.Add(i); Console.WriteLine(list.Count * 2); } }