#include <bits/stdc++.h>
#define ll long long
#define endl '\n'

using namespace std;

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

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

	cout << ans << '\n';

	return 0;
}