output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M
      A_1 B_1
      \vdots
      A_M B_M
attempt: N, M = map(int, input().split())
  mInfos = [list(map(int, input().split())) for _ in range(M)]
  gl = [0] * N
  mc = [0] * N
  gc = 0
  guru = []
  for i in range(M):
      mInfo = mInfos[i]
      p1 = mInfo[0]
      p2 = mInfo[1]
      naiflag = True
      if gl[p1 - 1] == 0 and gl[p2 - 1] == 0:
          gl[p1 - 1] = gc + 1
          gl[p2 - 1] = gc + 1
          mc[gc] = 2
          gc += 1
      elif gl[p1 - 1] != 0:
          gl[p2 - 1] = gl[p1 - 1]
          mc[p1 - 1] += 1
      elif gl[p2 - 1] != 0:
          gl[p1 - 1] = gl[p2 - 1]
          mc[p2 - 1] += 1
      else:
          gl = [gl[p1 - 1] if j == gl[p2 - 1] else j for j in gl]
          mc[p2 - 1] = 0
          gc -= 1
  mi = 0
  for i in range(1, gc + 1):
      dd = gl.count(i)
      mi = max(mi, dd)
  print(mi)
  
problem_description: Statement
  
  There are N persons called Person 1 through Person N.
  
  You are given M facts that "Person A_i and Person B_i are friends." The same
  fact may be given multiple times.
  
  If X and Y are friends, and Y and Z are friends, then X and Z are also
  friends. There is no friendship that cannot be derived from the M given facts.
  
  Takahashi the evil wants to divide the N persons into some number of groups so
  that every person has no friend in his/her group.
  
  At least how many groups does he need to make?
samples: [{"input": "5 3\n    1 2\n    3 4\n    5 1", "output": "3\n    \n\nDividing them into three groups such as \\\\{1,3\\\\}, \\\\{2,4\\\\}, and \\\\{5\\\\}\nachieves the goal.\n\n* * *"}, {"input": "4 10\n    1 2\n    2 1\n    1 2\n    2 1\n    1 2\n    1 3\n    1 4\n    2 3\n    2 4\n    3 4", "output": "4\n    \n\n* * *"}, {"input": "10 4\n    3 1\n    4 1\n    5 9\n    2 6", "output": "3"}]