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)

// Code Forces
#include<bits/stdc++.h>
#define ll long long int
#define MOD 1000000007
#define pi 3.1415926535
#define fi first
#define se second
#define vec vector
#define str string
#define FOR(i,n) for(int i=0;i<n;i++)
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fast ios_base::sync_with_stdio(false);  cin.tie(NULL);
#define dvec(v) vec < ll > v
#define sortA(v) sort(v.begin(),v.end())
#define sortD(v) sort(v.begin(),v.end(),greater <int> ())

using namespace std;

int main(){
    fast
    ll x=0;
    cin>>x;
    ll res=0;
    res=(x/500)*1000;
    ll a=x%500;
    res+=((a/5)*5);
    cout<<res;
    // my code
    return 0;
}