#include <bits/stdc++.h>     //   All praise is due to Allah alone, and peace and blessings be
using namespace std;         //         upon him, after whom there is no other Prophet.


int32_t main() {
    cin.tie(0)->sync_with_stdio(false);

    function<void()> Test_Case = [&]() {
        int n; cin >> n;
        int64_t sum = 0;
        sum += (n / 500) * 1000;
        n %= 500;
        sum += (n / 5) * 5;
        cout << sum << '\n';
    };

    int32_t Case = 1;    //cin >> Case;
    for (int T = 1; T <= Case; T++) {
        Test_Case();
    }
    return 0;
}