
'''simple docstring'''





import re

from filelock import FileLock


try:
      import nltk

      SCREAMING_SNAKE_CASE     =       True
except (ImportError, ModuleNotFoundError):
      SCREAMING_SNAKE_CASE     =       False

if NLTK_AVAILABLE:
      with FileLock(""".lock""") as lock:
            nltk.download("""punkt""", quiet=True)







def snake_case_     (					lowercase__		):
  re.sub("<n>"   ,       ""   ,       lowercase__		)  # remove pegasus newline char
  assert NLTK_AVAILABLE, "nltk must be installed to separate newlines between sentences. (pip install nltk)"
  return "\n".join(nltk.sent_tokenize(lowercase__		)		)





'''simple docstring'''





def snake_case_     (					lowercase__		):

  if len(lowercase__		) <= 1:
    return [tuple(lowercase__		)]

  UpperCAmelCase__      :					Union[str, Any]				       =							[]

  def generate(lowercase__   ,       lowercase__		):
    UpperCAmelCase__      :					str				       =							[0] * n
    res.append(tuple(lowercase__		)		)

    UpperCAmelCase__      :					Any				       =							0
    while i < n:
      if c[i] < i:
        if i % 2 == 0:
          UpperCAmelCase__       ,			UpperCAmelCase__      :					str				       =							arr[i], arr[0]
        else:
          UpperCAmelCase__       ,			UpperCAmelCase__      :					Optional[Any]				       =							arr[i], arr[c[i]]
        res.append(tuple(lowercase__		)		)
        c[i] += 1
        UpperCAmelCase__      :					List[str]				       =							0
      else:
        UpperCAmelCase__      :					Dict				       =							0
        i += 1

  generate(len(lowercase__		)   ,       lowercase__		)
  return res


if __name__ == "__main__":
      SCREAMING_SNAKE_CASE     =       input("""Enter numbers separated by a comma:\n""").strip()
      SCREAMING_SNAKE_CASE     =       [int(item) for item in user_input.split(""",""")]
      print(heaps(arr))



