#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <math.h>
#include <functional>
#include <iomanip>
#include <bitset>
#include <numeric>
#include <queue>
#include <map>
#include <cstdint>
#include <set>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
const long long mod = 1000000007;
typedef long long int ll;
typedef pair<ll, ll> P;
const vector<int> di = { -1, 0, 1, 0 };
const vector<int> dj = { 0, 1, 0, -1 };
const double PI = 3.14159265358979323846;


int main() {

	int x;
	cin >> x;
	int five_hund = 0;
	int five = 0;

	five_hund = x / 500;
	five = (x % 500) / 5;

	cout << five_hund * 1000 + five * 5 << endl;


	return 0;

}


/*
    -ensure correct output format
    -ensure printing required output
    -reread the problem statement
  */

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll>pll;
typedef pair<ll,pair<ll,ll>>plll;
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL));
#define vll(v) v.begin(),v.end()
#define all(x) x.rbegin(),x.rend()
#define min3(a, b, c)   min(a, min(b, c))
#define max3(a, b, c)   max(a, max(b, c))
#define F first
#define S second
#define in  freopen("input.txt", "r", stdin)
#define out  freopen("output.txt", "w", stdout)
#define minheap int,vector<int>,greater<int>
#define pb push_back
#define eb emplace_back
#define ischar(x)  (('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z'))
#define isvowel(ch) ((ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u')||(ch=='A'|| ch=='E' || ch=='I'|| ch=='O'|| ch=='U'))
#define bug cout<<"BUG"<<endl;
const int Max = 2e6 + 10;
const int Mod = 1e9 + 7;
const double PI  =3.141592653589793238463;
bool compare(const pair<ll,ll> &a, const pair<ll,ll> &b)
{
       return (a.first > b.first);
}
ll lcm(ll a,ll b)
{
    if(a==0 || b==0)return 0;

    return a/__gcd(a,b)*b;
}

void input(ll ara[],ll n)
{
    for(ll i=0; i<n; i++)cin>>ara[i];
}
void print(ll ara[],ll n)
{
    for(ll i=0; i<n; i++)
        cout<<ara[i]<<" ";
    cout<<endl;
}


int main()
{

   fastread();

   ll i,j,n,m,p,a,sum=0,k,t,b,c,d,cnt=0,q,l,r,ans=0;

      bool flag=false;

      string str;

      cin>>n;

      m=n/500;

      n%=500;

      m*=1000;

      a=n/5;
      m+=(a*5);

      cout<<m<<endl;













}

