def count_bidirectional(test_list):
  
  res = 0
  for idx in range(0, len(test_list)):
    for iidx in range(idx + 1, len(test_list)):
      if test_list[iidx][0] == test_list[idx][1] and test_list[idx][1] == test_list[iidx][0]:
        res += 1
  return (str(res)) 
def count_bidirectional(test_list):
    res = 0
    for idx in range(0, len(test_list)):
       
        for iidx in range(idx + 1, len(test_list)):
            if (
                test_list[idx][1] == test_list[iidx][0]
                and test_list[idx][1] == test_list[iidx][0]
            ):
                res += 1
    return str(res)