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 PyPy3 (7.3.0) (judge verdict: Time Limit Exceeded)

n, m = map(int, input().split())
uniquePair = set()
for i in range(m):
  a, b = map(int, input().split())
  uniquePair.add((a, b) if(a<b) else (b, a))
uniquePair = sorted(uniquePair, key = lambda x:x[0])
masterGroup = [{1}]
for a, b in uniquePair:
  inGroup = False
  for group in masterGroup:
    if(a in group or b in group):
      inGroup = True
      group.add(a)
      group.add(b)
      break
    else:
      continue
  if(not inGroup):
  	masterGroup.append({a, b})
result = 0
for i in masterGroup:
  result = max(result, len(i))
print(result)