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: # def friends(arr):
  #     table = [{}]
  #     for a in arr:
  #         seted = False
  #         for t in table:
  #             if a[0] in t or a[1] in t:
  #                 seted = True
  #                 t.add(a[0])
  #                 t.add(a[1])
  #         if not seted:
  #             table.append({a[0], a[1]})
  #
  #     return max(table, key=len)
  # def start():
  #     n, m = [int(x) for x in input().split(" ")]
  #     arr = []
  #     while m:
  #         arr.append([int(x) for x in input().split(" ")])
  #         m -= 1
  #     print(len(friends(arr)))
  # start()
  
  def friends(n,arr):
      import collections
      graph = collections.defaultdict(list)
      for i in range(len(arr)):
          graph[arr[i][0]].append(arr[i][1])
          graph[arr[i][1]].append(arr[i][0])
      visited = [False]*(n+1)
      maxi = 0
      for i in range(1,n+1):
          if not visited[i]:
              queue = collections.deque()
              queue.append(i)
              visited[i] = True
              temp = 0
              while queue:
                  temp += 1
                  s = queue.popleft()
                  for t in graph[s]:
                      if not visited[t]:
                          queue.append(t)
                          visited[t] = True
              maxi = max(maxi, temp)
      return maxi
  
  def start():
      n, m = [int(x) for x in input().split(" ")]
      arr = []
      while m:
          arr.append([int(x) for x in input().split(" ")])
          m -= 1
      print((friends(n,arr)))
  start()
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"}]