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.Linq;

namespace AtCoder {
    partial class Program {
        static void Main(string[] args) {

            var Input = Convert.ToInt32(Console.ReadLine());
            var Coins = new int[] { 500, 5 };
            var Points = new int[] { 1000, 5 };

            int point = 0;
            for (int i = 0; i < Coins.Length; i++)
            {
                point += Input / Coins[i] * Points[i];
                Input = Input % Coins[i];
            }
            /*foreach (var coin in Enumerable.Zip(Coins, Points))
            {
                point += Input / coin.First * coin.Second;
                Input = Input % coin.First;
            }*/

            Console.WriteLine(point);
        }
    }

}