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

using ll = long long;

void solve(int T) {
	ll n; cin >> n;
	ll ans = n / 500 * 1000;
	n %= 500;
	ans += n / 5 * 5;
	cout << ans << "\n";
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
#ifdef MYPC
	cout << "==== OUTPUT ====\n";
#endif
	int t = 1;
	for(int i = 1; i <= t; i++) {
		solve(i);
	}
}