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;

namespace _20200328_ABC160B
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = ReadStringList(1);

            int X = int.Parse(input[0]);

            int num500 = X / 500;
            X -= num500 * 500;
            int num5 = X / 5;

            uint result = 1000u * (uint)num500 + 5u * (uint)num5;

            Console.WriteLine(result);
        }

        private static List<string> ReadStringList(int numberOfLines)
        {
            var stringList = new List<string>();

            for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
            {
                stringList.Add(Console.ReadLine().Trim());
            }

            return stringList;
        }

    }
}