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>
#pragma GCC optimize("O3")
#pragma GCC target("sse4")

using namespace std;

#define FOR(a,b) for(int a=0;a<b;a++)
#define F0R(a,b,c) for(int a = b; a<=c; a++)
#define f first
#define s second
#define m0(x) memset(x,0,sizeof(x))

typedef pair<int,int> pi;
typedef long long ll;
typedef vector<int> vi;
typedef vector<pi> vpi;

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    unsigned int x; cin >> x;
    unsigned int total = 0;
    int b = x/500;
    total = 1000*b; x -= 500*b;
    x -= x%5;
    total += x;
    cout << total << endl;
    return 0;
}