output_description: Print the minimum total cost required to determine all of A_1, A_2, ..., A_N.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M
      X_1 Y_1 Z_1
      X_2 Y_2 Z_2
      \vdots
      X_M Y_M Z_M
attempt: a = input().split()
  a = list(map(int, a))
  i = 0
  dif = []
  while i < a[1]:
      c = input().split()
      c = list(map(int, c))
      c.sort()
      if c[-1] - c[0] == 1:
          dif.append(2)
      elif c[-1] - c[0] == 0:
          dif.append(1)
      elif c[-1] - c[0] >= 2:
          dif.append(c[-1] - c[0])
      i += 1
  dif.sort()
  print(dif[-1])
  
problem_description: Statement
  
  There are N cards placed face down in a row. On each card, an integer 1 or 2
  is written.
  
  Let A_i be the integer written on the i-th card.
  
  Your objective is to guess A_1, A_2, ..., A_N correctly.
  
  You know the following facts:
  
    * For each i = 1, 2, ..., M, the value A_{X_i} + A_{Y_i} + Z_i is an even number.
  
  You are a magician and can use the following magic any number of times:
  
  **Magic** : Choose one card and know the integer A_i written on it. The cost
  of using this magic is 1.
  
  What is the minimum cost required to determine all of A_1, A_2, ..., A_N?
  
  It is guaranteed that there is no contradiction in given input.
samples: [{"input": "3 1\n    1 2 1", "output": "2\n    \n\nYou can determine all of A_1, A_2, A_3 by using the magic for the first and\nthird cards.\n\n* * *"}, {"input": "6 5\n    1 2 1\n    2 3 2\n    1 3 3\n    4 5 4\n    5 6 5", "output": "2\n    \n\n* * *"}, {"input": "100000 1\n    1 100000 100", "output": "99999"}]