input: Write a function to calculate the sum of the series 1 + ½ + ⅓ + ... + 1/n. The function should take an integer n as input and return the resulting sum. If n is 0 or negative, return 0.
  assert seriesSum(5) == 2.283333333333333
  assert seriesSum(1) == 1.0
  assert seriesSum(0) == 0
  assert seriesSum(-3) == 0
output: def seriesSum(n):
      if n <= 0:
          return 0
      sum = 0
      for i in range(1, n + 1):
          sum += 1 / i
      return sum