Problem:
Score : 200 points

Problem Statement

Takahashi loves gold coins. He gains 1000 happiness points for each 500-yen coin he has and gains 5 happiness points for each 5-yen coin he has. (Yen is the currency of Japan.)

Takahashi has X yen. If he exchanges his money so that he will gain the most happiness points, how many happiness points will he earn?

(We assume that there are six kinds of coins available: 500-yen, 100-yen, 50-yen, 10-yen, 5-yen, and 1-yen coins.)

Constraints

0 \leq X \leq 10^9

X is an integer.

Input

Input is given from Standard Input in the following format:

X

Output

Print the maximum number of happiness points that can be earned.

Sample Input 1

1024

Sample Output 1

2020

By exchanging his money so that he gets two 500-yen coins and four 5-yen coins, he gains 2020 happiness points, which is the maximum number of happiness points that can be earned.

Sample Input 2

0

Sample Output 2

0

He is penniless - or yenless.

Sample Input 3

1000000000

Sample Output 3

2000000000

He is a billionaire - in yen.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using static System.Console;
class Program
{
	static void Main(string[] args)
	{
		// 整数の入力
		long a = long.Parse(Console.ReadLine());
		// スペース区切りの整数の入力
		//string[] NMK = Console.ReadLine().Split(' ');
		//long N = long.Parse(NMK[0]);
		//long K = long.Parse(NMK[1]);
		//string s = Console.ReadLine();
		long happy = 0;
		happy += a/500*1000;
		a = a%500;

		happy += a/5*5;

		Console.WriteLine(happy + "");

		// 文字列の入力
		//string s = Console.ReadLine();
		//出力
		//Console.WriteLine((a+b+c) + " " + s);
	}
}