text: import re
  node = set([])
  with open('HVR_5.txt', 'r') as f:
    for line in f.readlines():
      line = re.sub(r'\n', '', line)
      a, b = line.split(' ')
      node.add(a)
      node.add(b)
  print(node)
  
  with open('HVR_5_metadata.txt', 'r') as f:
    for line in f.readlines():
      a, b = line.split(' ')
      if a not in node:
        continue
      print(str(a) + ' ' + str(b)),
  # print(node)
  # print(len(node))