#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
using ll = long long;

void solve() {
    ll n;
    cin >> n;
    ll ans = (n / 500) * 1000;
    n = (n % 500);
    ans += (n / 5) * 5;
    cout << ans << endl;
    return;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case " << t << ": ";
        solve();
    }
    return 0;
}