input: def calculate_minimum_chairs(s: str) -> int:
      """
      Given a string s, simulate the sequence of events at each second:
  
      If s[i] == 'E', an individual enters and occupies an available chair.
      If s[i] == 'L', an individual vacates a chair in the waiting area.
      Determine the minimum number of chairs required to ensure that everyone entering can have a seat, starting with an empty waiting room.
  
      Examples:
      >>> s = "EEEEEEE"
      7
      >>> s = "ELELEEL"
      2
  
      Constraints:
      1 <= s.length <= 50
      s is made up only of the letters 'E' and 'L'.
      s describes a valid sequence of arrivals and departures.
      """
output:     
      occupied = 0
      max_chairs = 0
  
      for char in s:
          if char == 'E':
              occupied += 1
          elif char == 'L':
              occupied -= 1
          max_chairs = max(max_chairs, occupied)
  
      return max_chairs
  