#include<bits/stdc++.h>
#ifdef Sabbir
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wsign-compare"
#endif
using namespace std;
#ifdef Sabbir
#include <E:\CodeBox\TempBox\Debug\debug.h>
#else
#define dbg(x...)
#endif
#define ll                 long long
#define all(x)             (x).begin(), (x).end()
#define in(v)               for(auto &b:v)cin>>b;
#define pb                  push_back
#define inf               (long long)1e8+7
const int mx=4e5+5;

void pagol(){
    int n;
    cin>>n;
    int ans=n/500;
    ans*=1000;
    int di=n%500;
    di/=5;
    cout<<ans+(di*5)<<endl;
 
}

int32_t main() {
  ios::sync_with_stdio(0);cin.tie(0);
    int t = 1;
   //cin>>t;
    while (t--) {

        pagol();
    }
    return 0;
}
//যদ্দপী, আমি তাহাতেই মুগ্ধ হইয়া গিয়াছি