// Author: Shawn Das Shachin-->(shawn_das)

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define pb push_back
#define mod 1000000007
#define srt(v) sort(v.begin(),v.end())
#define rsrt(v) sort(v.rbegin(),v.rend())
#define OPTIMIZE_IO ios::sync_with_stdio(false); cin.tie(nullptr);

int main() {
    OPTIMIZE_IO;
    ll n;
    cin>>n;

    ll lan=n/500;
    ll vib=(n%500)/5;

    cout<<lan*1000+vib*5<<endl;

    
    return 0;
}