new_contents: keep = list(range(1, 1501))
  remove = False
  
  while(len(keep) > 1):
      n_keep = []
      
      for person in keep:
          if not remove:
              n_keep.append(person)
              
          remove = not remove
  
      keep = n_keep
  
  print(keep)
  
subject: Solve knowit 2017/dec10