#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using i128 = __int128;

void solve () {
  ll n;
  cin >> n;
  int ans = 0;
  while (1) {
    if (n < 500) break;
    n -= 500;
    ans += 1000;
  }
  while (1) {
    if (n < 5) break;
    n -= 5;
    ans += 5;
  }
  cout << ans << '\n';
}

int32_t main() {
  auto begin = std::chrono::high_resolution_clock::now();
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int T = 1;
 // cin >> T;
  for(int i = 1; i <= T; i++) {
    //  cout << "Case " << i << ": ";
      solve();
  }
  auto end = std::chrono::high_resolution_clock::now();
  auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
  cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
  return 0;
}