input: Write a function to calculate the sum of squares of all the numbers from 1 to N. If N is less than 1, return 0.
  
  def sum_of_squares(n):
      if n < 1:
          return 0
      result = 0
      for i in range(1, n+1):
          result += i**2
      return result
  
  assert sum_of_squares(10) == 385
  assert sum_of_squares(0) == 0
  assert sum_of_squares(1) == 1
  assert sum_of_squares(5) == 55
output: def sum_of_squares(n):
      if n < 1:
          return 0
      result = 0
      for i in range(1, n+1):
          result += i**2
      return result