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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define all(a) (a).begin(), (a).end()
typedef long long ll;
#define INF 1e9
typedef pair<int, int> P;

/* 　"assert"    assert(A：条件式)で　Aが真なら処理は続行、偽ならプログラムを終了する　*/

/*　　ラムダ式　　 auto a = [キャプチャ](パラメータ){ 処理 }  */

/* string型　メンバ関数　substr()    replace()  */

int main(){
    ll x; cin >> x;
    ll happiness = 0;
    happiness += 1000*(x/500);
    x -= 500*(x/500);
    
    happiness += 5*(x/5);
    
    cout << happiness << endl;
    

}