input: Write a function to calculate the cube of a given integer and print the result. The function should take an integer input from the user, calculate its cube, and then print the cube value.
  assert cube_of_number(3) == 27
  assert cube_of_number(0) == 0
  assert cube_of_number(-2) == -8
  assert cube_of_number(5) == 125
  assert cube_of_number(1) == 1
output: def cube_of_number(n):
      return n ** 3