#include <bits/stdc++.h>
using namespace std;

int main() {
    long long N;
    cin >> N;

    long long lanterns = N / 500;

    long long tokens_rem = N % 500;

    long long banners = tokens_rem / 5;

    long long points_fest = (lanterns * 1000) + (banners * 5);

    cout << points_fest << endl;

    return 0;
}