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 <algorithm>
#include <cstdio>
#include <vector>
#include <math.h>
#include <iomanip>
#include <bitset>
#include <string>
#include <cstring>
#include <stdlib.h>
#include <utility>
#include <set>
#include <map>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> pairs;

#define MOD 998244353


ll gcd(ll a,ll b){
    if (a%b==0)return(b);
    else return(gcd(b,a%b));
}

bool primeNumber(ll n){
    if(n < 2) return false;
    else{
        for(ll i = 2; i * i <= n; i++){
            if(n % i == 0) return false;
        }
        return true;
    }
}


  

int main(){
    ll x;
    cin>>x;
    ll count = 0;
    
    for(ll i = 0; i<x; i++){
        if(x >= 500){
            x -= 500;
            count += 1000;
        }else if(x>=5){
            x -= 5;
            count += 5;
        }else break;
    }
    cout<<count<<endl;
    return 0;
}