Problem: 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?

Submission attempts (in order):
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    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)]


N, M=map(int,input().split())
UF=UnionFind(N)

for _ in range(M):
    A,B=map(int,input().split())
    UF.union(A,B)

ans=0

for i in range(N):
    ans = max(ans, UF.size(i))
 
 print(ans)

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    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)]


N, M=map(int,input().split())
UF=UnionFind(N)

for _ in range(M):
    A,B=map(int,input().split())
    UF.union(A-1,B-1)

ans=0

for i in range(N):
    ans = max(ans, UF.size(i));
 
 print(ans)





class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    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)]


N, M=map(int,input().split())
UF=UnionFind(N)

for _ in range(M):
  A,B=map(int,input().split())
  UF.union(A,B)

ans=0

for i in range(N):
  ans = max(ans, UF.size(i));
 
 print(ans)

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    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)]


N, M=map(int,input().split())
UF=UnionFind(N)

for _ in range(M):
    A,B=map(int,input().split())
    UF.union(A-1,B-1)

ans=0

for i in range(N):
    ans = max(ans, UF.size(i))
 
 print(ans)

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    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)]


N, M = map(int, input().split())
UF = UnionFind(N)

for _ in range(M):
    A, B = map(int, input().split())
    UF.union(A - 1, B - 1)

ans = 0

for i in range(N):
    ans = max(ans, UF.size(i))

print(ans)


Verdicts: Runtime Error

Runtime Error

Runtime Error

Runtime Error

Accepted