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)

N,M = map(int,input().split())
if M == 0:
  print(1)
else:
  F = list((sorted(map(int,input().split()))) for i in range(M))
  L = list(map(list,set(map(tuple,F))))
  
  team = []
  for i in range(len(L)):
    if i == 0:
      team.append(L[i])
    else:
      for j in range(len(team)):
        if L[i][0] in team[j] and L[i][1] not in team[j]:
          team[j].append(L[i][1])
          break
        elif L[i][0] not in team[j] and L[i][1] in team[j]:
          team[j].append(L[i][0])
          break
      else:
        team.append(L[i])
team_l = [len(k) for k in team]
print(max(team_l))