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