def add_changes(last, recent):
  """
    Change num string(today and yesterday's stat) to num, then subtrack the difference between yesterday's stat and today's stat.
    After getting the difference, add them to the num string(today's stat) with parentheses.
    Example: 
      Yesterday's total COVID19 cases: "12,345" -> last[0]
      Today's total COVID19 cases: "12,550" -> recent[0]
      "12,550 (+205)" -> result[0]

    last: Yesterday's [COVID19 cases, cured cases, deaths]
    recent: Today's [COVID19 cases, cured cases, deaths]
  """
  prev1 = int(last[0].split(" ")[0].replace(",", ""))
  prev2 = int(last[1].split(" ")[0].replace(",", ""))
  prev3 = int(last[2].split(" ")[0].replace(",", ""))

  recent1 = int(recent[0].split(" ")[0].replace(",", ""))
  recent2 = int(recent[1].split(" ")[0].replace(",", ""))
  recent3 = int(recent[2].split(" ")[0].replace(",", ""))

  fin1 = " (+" + "{:,}".format(recent1 - prev1) + ")"
  fin2 = " (+" + "{:,}".format(recent2 - prev2) + ")"
  fin3 = " (+" + "{:,}".format(recent3 - prev3) + ")"

  result = []

  if (recent1 != prev1):
    result.append(recent[0] + fin1)
  else:
    result.append(recent[0])

  if (recent2 != prev2):
    result.append(recent[1] + fin2)
  else:
    result.append(recent[1])

  if (recent3 != prev3):
    result.append(recent[2] + fin3)
  else:
    result.append(recent[2])

  return result