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 mainspring cout<<"mainspring\n";
	#define barrel cout<<"barrel\n";
	#define escapement cout<<"escapement\n";

	#define pb push_back
	#define eb emplace_back
	#define all(v) (v).begin(), (v).end() 
	#define sz(v) (int)((v).size())
	#define fs first
	#define sd second
	#define tik(i,a,b) for(int i = a; i < b; i++)
	#define tok(i,a,b) for(int i = a; i >= b; i--)
	#define error(args...) {string _s = #args; replace(_s.begin(), _s.end(), ',',' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it,args);}

	typedef long long ll;
	typedef unsigned long long ull;

	#define int ll 

	typedef pair < int, int > pi;
	typedef pair < pi, int > ppi;

	typedef vector < int > vi;
	typedef vector < vector < int > > vvi;
	typedef vector < pi > vpi;
	typedef vector < vpi > vvpi;
	typedef vector < ppi > vppi;

	void fast() {
	    ios_base::sync_with_stdio(false);
	    cin.tie(NULL);
	}

	void err(istream_iterator<string> it) {cout << endl;}
	template<typename T, typename... Args>
	void err(istream_iterator<string> it, T a, Args... args) {
	    cerr << *it << " = " << a << " ";
	    err(++it, args...);
	}

	ll pow(ll x, ll y) {
		if(y == 0)
		return 1;
		ll temp = pow(x, y/2);
		temp = (temp*temp);
		if(y%2 == 1)
			temp *= x;
		return temp;
	}

	int32_t main() {
		int x;
		cin >> x;
		int res = 1000*(x/500);
		x -= 500*(x/500);
		res += 5*(x/5);
		cout << res;	
	}