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)

     //k_tourist
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#include<bits/stdc++.h>
#define mod 1000000007
#define ll long long
#define mx 500005
#define non __builtin_popcount
#define ml map<ll, ll> 
#define uml unordered_map<ll, ll>
#define ms map<string , ll> 
#define all(a) (a).begin(),(a).end()
#define ff first
#define ss second
#define pl pair<ll, ll>
#define vl vector<ll>
#define vll vector<pl>
#define tpl pair<ll, pl>
#define vlll vector<tpl>
#define vs vector<string>
#define pb push_back
#define mk make_pair
#define M_PI 3.14159265358979323846
#define endl '\n'
#define fst ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define si(x) scanf("%d",&x)
#define sl(x) scanf("%I64d",&x)
#define inf ((ll)1e18 + 1)
#define bs binary_search
#define pq priority_queue
#define ub upper_bound
#define lb lower_bound
#define pow powr
#define sp(a) setprecision(a)
#define rep(i,a,b)  for (i=(a);i<(b);i++)
#define nrep(i,a,b) for (i=(a);i>(b);i--)
using namespace std;
using namespace __gnu_pbds;  

typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update>  ordered_set;
 
ll powr(ll a,ll b)
{
	ll res=1;
	while(b)
	{
		if(b&1)res=(res*a)%mod;
		a=(a*a)%mod;
		b>>=1;
	}
	return res;
}

void flag(ll fl){

	if(fl)
	cout<<"No";
	else
	cout<<"Yes";
}


void bta_de_yarr(){

	ll n, i, j, m, ans, fl=0;

    cin>>n;

    ans= (n/500)*1000 ;
    n%= 500;

    ans+= ((n/5)*5);

    

	cout<<ans;
	// flag(fl);
	cout<<endl;
}

int main(){
    fst

	// freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
	ll t, i;
    t= 1;
	// cin>>t;
    
    rep(i, 1, t+1){

        // cout<<"Case #"<<i<<":"<<" ";
        bta_de_yarr();
    }
    return 0;
}