Buggy python submission (verdict: Runtime Error):
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(set(a)))


Fixed submission:
import sys
sys.setrecursionlimit(100000)
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  if a>b:
    a=g
    g=b
    b=a
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(set(a)))

Buggy python submission (verdict: Runtime Error):
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(a))


Fixed submission:
import sys
sys.setrecursionlimit(100000)
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  if a>b:
    a=g
    g=b
    b=a
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(set(a)))

Buggy python submission (verdict: Runtime Error):
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(in,input().split())
  uf.merge(a-1,b-1)
print(len(u.parent))

Fixed submission:
import sys
sys.setrecursionlimit(100000)
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  if a>b:
    a=g
    g=b
    b=a
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(set(a)))

Buggy python submission (verdict: Runtime Error):
n,m = map(int,input().split())
a = []
for i in range(n):
  b,c,d = map(int,input().split())
  if b in a and c in a:
    m = m-1
  a.append(b)
  a.append(c)
print(n-m)

Fixed submission:
import sys
sys.setrecursionlimit(100000)
n,m=map(int,input().split())
class UnionFind(object):
    def __init__(self, N):
        self.parent = [i for i in range(N)]
 
    def merge(self, a, b):
        pa = self.root(a)
        pb = self.root(b)
        self.parent[pa] = pb
    
    def root(self, x):
        p = self.parent[x]
        if p == x:
            return x
        else:
            r = self.root(p)
            self.parent[x] = r
            return r
u=UnionFind(n)
for i in range(m):
  a,b,c=map(int,input().split())
  if a>b:
    a=g
    g=b
    b=a
  u.merge(a-1,b-1)
a=[0]*n
for i in range(n):
  a[i]=u.root(i)
print(len(set(a)))