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(5)==55
  assert sum_of_squares(1)==1
  assert sum_of_squares(0)==0
  assert sum_of_squares(-3)==0
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