#include <bits/stdc++.h>

using namespace std;
using ll = long long;
const ll mod = 1e9 + 7;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    ll n;
    cin >> n;
    
    ll ans = (n / 500) * 1000;
    
    n %= 500;
    
    cout << ans + (n / 5) * 5 << "\n";


    return 0;
}
// Author : Raj (raj_singh35)