
import re

from filelock import FileLock


try:
			import nltk

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

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



def 						lowercase_      (       A__		)							->							str:
				"""simple docstring"""

				re.sub("<n>"			,		""			,		a__		)  # 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(a__		)		)



def 						lowercase_      (       A__ = 1000		)							->							int:
    """simple docstring"""

    return sum(2 * a * ((a - 1) // 2) for a in range(3			,		n + 1		)		)


if __name__ == "__main__":
   print(solution())

