text: """
  a b
  b c
  b d
  d a
  q w
  q t
  a s
  a w
  w e
  w p
  q a
  find reachability
  """
  li=list(map(int,input().split(" ")))
  grapg_dict=dict()
  
  for i in li:
      if grapg_dict.get(i[0]):
          grapg_dict[i[0]].append(i[1])
      else:
          grapg_dict[i[0]]=[]
          grapg_dict[i[0]].append(i[1])
  print(grapg_dict)
  
  
  
  