'''

自宅用PCでの解答

'''

import math

#import numpy as np

import itertools

import queue

import bisect

from collections import deque,defaultdict

import heapq as hpq

from sys import stdin,setrecursionlimit

#from scipy.sparse.csgraph import dijkstra

#from scipy.sparse import csr_matrix

ipt = stdin.readline

setrecursionlimit(10**7)

mod = 10**9+7 #998244353

dir = [(-1,0),(0,-1),(1,0),(0,1)]

alp = "abcdefghijklmnopqrstuvwxyz"



#UnionFindのクラス,0-indexed

class UnionFind():

    def __init__(self, n):

        self.n = n

        # parents = [-1,0,-4,1,1,1]のように、親の添字かマイナス要素数を表す

        self.parents = [-1] * n

    # find: xの親がすべてrootになる。これにより計算量削減(O(N) for all (not each))

    def find(self, x):

        if self.parents[x] < 0:

            return x

        else:

            self.parents[x] = self.find(self.parents[x])

            return self.parents[x]

    def union(self, x, y):

        x = self.find(x)

        y = self.find(y)

        if x == y:

            return

        if self.parents[x] > self.parents[y]:

            x, y = y, x

        self.parents[x] += self.parents[y]

        self.parents[y] = x

    def size(self, x):

        return -self.parents[self.find(x)]

    def same(self, x, y):

        return self.find(x) == self.find(y)

    def members(self, x):

        root = self.find(x)

        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):

        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):

        return len(self.roots())

    def all_group_members(self):

        return {r: self.members(r) for r in self.roots()}

    def __str__(self):

        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())



def main():

    n,m = list(map(int,ipt().split()))

    uf = UnionFind(n)

    for i in range(m):

        a,b = list(map(int,ipt().split()))

        uf.union(a-1,b-1)



    print((-min(uf.parents)))



    return None



if __name__ == '__main__':

    main()

'''

自宅用PCでの解答

'''

import math

#import numpy as np

import itertools

import queue

import bisect

from collections import deque,defaultdict

import heapq as hpq

from sys import stdin,setrecursionlimit

#from scipy.sparse.csgraph import dijkstra

#from scipy.sparse import csr_matrix

ipt = stdin.readline

setrecursionlimit(10**7)

mod = 10**9+7 #998244353

dir = [(-1,0),(0,-1),(1,0),(0,1)]

alp = "abcdefghijklmnopqrstuvwxyz"



#UnionFindのクラス,0-indexed

class UnionFind():

    def __init__(self, n):

        self.n = n

        # parents = [-1,0,-4,1,1,1]のように、親の添字かマイナス要素数を表す

        self.parents = [-1] * n

    # find: xの親がすべてrootになる。これにより計算量削減(O(N) for all (not each))

    def find(self, x):

        if self.parents[x] < 0:

            return x

        else:

            self.parents[x] = self.find(self.parents[x])

            return self.parents[x]

    def union(self, x, y):

        x = self.find(x)

        y = self.find(y)

        if x == y:

            return

        if self.parents[x] > self.parents[y]:

            x, y = y, x

        self.parents[x] += self.parents[y]

        self.parents[y] = x

    def size(self, x):

        return -self.parents[self.find(x)]

    def same(self, x, y):

        return self.find(x) == self.find(y)

    def members(self, x):

        root = self.find(x)

        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):

        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):

        return len(self.roots())

    def all_group_members(self):

        return {r: self.members(r) for r in self.roots()}

    def __str__(self):

        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())



def main():

    n,m = list(map(int,ipt().split()))

    uf = UnionFind(n+1)

    for i in range(m):

        a,b = list(map(int,ipt().split()))

        uf.union(a,b)



    print((-min(uf.parents)))



    return None



if __name__ == '__main__':

    main()

"""
自宅用PCでの解答
"""
import math

# import numpy as np
import itertools
import queue
import bisect
from collections import deque, defaultdict
import heapq as hpq
from sys import stdin, setrecursionlimit

# from scipy.sparse.csgraph import dijkstra
# from scipy.sparse import csr_matrix
ipt = stdin.readline
setrecursionlimit(10**7)
mod = 10**9 + 7  # 998244353
dir = [(-1, 0), (0, -1), (1, 0), (0, 1)]
alp = "abcdefghijklmnopqrstuvwxyz"
# UnionFindのクラス,0-indexed
class UnionFind:
    def __init__(self, n):
        self.n = n
        # parents = [-1,0,-4,1,1,1]のように、親の添字かマイナス要素数を表す
        self.parents = [-1] * n

    # find: xの親がすべてrootになる。これにより計算量削減(O(N) for all (not each))
    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.parents[x] > self.parents[y]:
            x, y = y, x
        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return "\n".join("{}: {}".format(r, self.members(r)) for r in self.roots())


def main():
    n, m = list(map(int, ipt().split()))
    uf = UnionFind(n)
    for i in range(m):
        a, b = list(map(int, ipt().split()))
        uf.union(a - 1, b - 1)
    print((-min(uf.parents)))
    return None


if __name__ == "__main__":
    main()

"""
自宅用PCでの解答
"""
import math

# import numpy as np
import itertools
import queue
import bisect
from collections import deque, defaultdict
import heapq as hpq
from sys import stdin, setrecursionlimit

# from scipy.sparse.csgraph import dijkstra
# from scipy.sparse import csr_matrix
ipt = stdin.readline
setrecursionlimit(10**7)
mod = 10**9 + 7  # 998244353
dir = [(-1, 0), (0, -1), (1, 0), (0, 1)]
alp = "abcdefghijklmnopqrstuvwxyz"
# UnionFindのクラス,0-indexed
class UnionFind:
    def __init__(self, n):
        self.n = n
        # parents = [-1,0,-4,1,1,1]のように、親の添字かマイナス要素数を表す
        self.parents = [-1] * n

    # find: xの親がすべてrootになる。これにより計算量削減(O(N) for all (not each))
    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.parents[x] > self.parents[y]:
            x, y = y, x
        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return "\n".join("{}: {}".format(r, self.members(r)) for r in self.roots())


def main():
    n, m = list(map(int, ipt().split()))
    uf = UnionFind(n + 1)
    for i in range(m):
        a, b = list(map(int, ipt().split()))
        uf.union(a, b)
    print((-min(uf.parents)))
    return None


if __name__ == "__main__":
    main()

-    uf = UnionFind(n) +    uf = UnionFind(n + 1) -        uf.union(a - 1, b - 1) +        uf.union(a, b)