Problem:
Score : 400 points

Problem 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?

Constraints

2 \leq N \leq 2\times 10^5

0 \leq M \leq 2\times 10^5

1\leq A_i,B_i\leq N

A_i \neq B_i

Input

Input is given from Standard Input in the following format:

N M
A_1 B_1
\vdots
A_M B_M

Output

Print the answer.

Sample Input 1

5 3
1 2
3 4
5 1

Sample Output 1

3

Dividing them into three groups such as \{1,3\}, \{2,4\}, and \{5\} achieves the goal.

Sample Input 2

4 10
1 2
2 1
1 2
2 1
1 2
1 3
1 4
2 3
2 4
3 4

Sample Output 2

4

Sample Input 3

10 4
3 1
4 1
5 9
2 6

Sample Output 3

3

Solution in Python (3.8.2) (judge verdict: Runtime Error)

#import sys
#sys.setrecursionlimit(99999999)


[n,m]=list(map(int,input().split()))
friends=[]
for i in range(m):
    friends.append(list(map(int,input().split())))

tomodachi=[[]for i in range(n)]

for i in range(m):
    tomodachi[friends[i][0]-1].append(friends[i][1]-1)
    tomodachi[friends[i][1]-1].append(friends[i][0]-1)

for i in range(n):
    tomodachi[i]=list(set(tomodachi[i]))

namelist=[1 for i in range(n)]
teams=[]

def haba(x,kari,tomodachi,namelist):
    for i in range(len(tomodachi[x])):
        if namelist[tomodachi[x][i]]==1:#生き残っているなら
            kari.append(tomodachi[x][i])
            namelist[tomodachi[x][i]]=0#殺す
            haba(tomodachi[x][i],kari,tomodachi,namelist)
    return(kari)
            


for i in range(n):
    if namelist[i]==1:
        teams.append(list(set(haba(i,[i],tomodachi,namelist))))

saidai=0

for i in range(len(teams)):
    if saidai<len(teams[i]):
        saidai=len(teams[i])

ans=saidai

print(ans)