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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

    $x = in_int();

    $cnt500 = floor($x / 500);
    $cnt5 = floor(($x - ($cnt500 * 500)) / 5);

    out(($cnt500 * 1000) + ($cnt5 * 5));
    
    /**
    * お手伝い関数さんたち
    */
    function in() {
        return trim(fgets(STDIN));
    }
    function in_int() {
        return (int)in();
    }
    function in_vals() {
        return explode(' ', in());
    }
    function in_ints() {
        return array_map('intval', in_vals());
    }
    function out($s) {
        echo $s . PHP_EOL;
    }
    function yes() {
        out('Yes');
    }
    function no() {
        out('No');
    }
    function factorial($n) { // 階乗
        if ($n > 0) {
            return $n *= factorial($n - 1);
        }
        return 1;
    }
    function is_palindrome($s) {  // 回文か
        return $s == strrev($s);
    }