text: import xml.etree.ElementTree as etree
  
  maxdepth = 0
  def depth(elem, level):
      global maxdepth
      # your code goes here
      if (level == maxdepth):
          maxdepth += 1
          
      for child in elem:
          depth(child, level + 1)
  
  if __name__ == '__main__':
      n = int(input())
      xml = ""
      for i in range(n):
          xml =  xml + input() + "\n"
      tree = etree.ElementTree(etree.fromstring(xml))
      depth(tree.getroot(), -1)
      print(maxdepth)
  