static TimedCache<Long> numComputers_cache = new TimedCache(10*60);

static long numComputers_cached() {
  long numComputers = 0;
  pcall {
    if (eq(numComputers_cache.get(), 0L)) numComputers_cache.clean();
    numComputers = numComputers_cache.get(func { getNumberOfComputers() });
  }
  ret numComputers;
}