#include <bits/stdc++.h>

using namespace std;

void solve(int cs) {
  int64_t j;
  cin >> j;
  int64_t ans = j / 500 * 1000;
  j %= 500;
  ans += j / 5 * 5;
  cout << ans << "\n";
}

int32_t main() {
  ios::sync_with_stdio(!cin.tie(0));
  int t = 1;
  // cin >> t;
  for (int i = 1; i <= t; ++i) {
    solve(i);
  }
  return 0;
}