

'''simple docstring'''







import math
import sys
def  UpperCAmelCase__      ( UpperCAmelCase__			)     ->     int:
       if number != int(lowerCAmelCase_			):
              raise ValueError("""the value of input must be a natural number"""			)
       if number < 0:
              raise ValueError("""the value of input must not be a negative number"""			)
       if number == 0:
              return 1
       A_		   = [-1] * (number + 1)
       A_		   = 0
       for i in range(1,    number + 1			):
              A_		   = sys.maxsize
              A_		   = int(math.sqrt(lowerCAmelCase_			)			)
              for j in range(1,    root + 1			):
                     A_		   = 1 + answers[i - (j**2)]
                     A_		   = min(lowerCAmelCase_,    lowerCAmelCase_			)
              A_		   = answer
       return answers[number]


if __name__ == "__main__":
      import doctest

      doctest.testmod()



'''simple docstring'''







def  UpperCAmelCase__      ( UpperCAmelCase__ = 10_00			)     ->     int:
       return sum(2 * a * ((a - 1) // 2) for a in range(3,    n + 1			)			)


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