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: Wrong Answer)

#include <iostream>
#include <string>
using namespace std;

void happiness(int yen){
    int happiness=0;
    while(yen!=0){
        if(yen>=500){
            yen-=500;
            happiness+=1000;
        }
        else if(yen>=100){
            yen-=100;
        }
        else if(yen>=50){
            yen-=50;
        }
        // else if(yen>=10){
          //  yen-=10;
       // }
        else if(yen>=5){
            yen-=5;
            happiness+=5;
        }
        else if(yen>=1){
            yen-=1;
        }
    }
    cout<<happiness;
}

int main(){
    int input;
    cin >> input;
    happiness(input);
}