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

#define FAST ios_base::sync_with_stdio(false);cin.tie(NULL);
using ll = long long;

int main() {
  FAST;

  ll n, i, mx, ans;
  cin >> n;

  mx = min(1000ll, n/5);

  ans = 0;
  for (i = 0; i <= mx; ++i) {
    ans = max(ans, i*5 + ((n-i*5)/500) * 1000);
  }

  cout << ans << "\n";

  return 0;
}