Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    while parent[a] != a:
        a = parent[a]
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Fixed submission:
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    ls = []
    while parent[a] != a:
        ls.append(a)
        a = parent[a]
    for l in ls:
        parent[l] = a
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    while parent[a] != a:
        a = parent[a]
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Fixed submission:
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    ls = []
    while parent[a] != a:
        ls.append(a)
        a = parent[a]
    for l in ls:
        parent[l] = a
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
n, m = [int(i) for i in sys.stdin.readline().split()]
already = set()
cnt = 0
ls = []
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    root_b = find_root(b)
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    while parent[a] != a:
        a = parent[a]
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

cnt = 0
_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Fixed submission:
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    ls = []
    while parent[a] != a:
        ls.append(a)
        a = parent[a]
    for l in ls:
        parent[l] = a
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
n, m = [int(i) for i in sys.stdin.readline().split()]
already = set()
cnt = 0
ls = []
parent = [i for i in range(n)]

def unite(a, b):
    if not is_same(a, b):
        parent[find_root(b)] = find_root(a)

def find_root(a):
    while parent[a] != a:
        a = parent[a]
    return a

def is_same(a, b):
    return find_root(a) == find_root(b)

for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

cnt = 0
_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Fixed submission:
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    ls = []
    while parent[a] != a:
        ls.append(a)
        a = parent[a]
    for l in ls:
        parent[l] = a
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
n, m = [int(i) for i in sys.stdin.readline().split()]
already = set()
cnt = 0
ls = []
parent = [i for i in range(n)]

def unite(a, b):
    if not is_same(a, b):
        parent[find_root(b)] = find_root(a)

def find_root(a):
    while parent[a] != a:
        a = parent[a]
    return a

def is_same(a, b):
    return find_root(a) == find_root(b)

for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

cnt = 0
_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))

Fixed submission:
import sys
sys.setrecursionlimit(10**7)
n, m = [int(i) for i in sys.stdin.readline().split()]
parent = [i for i in range(n)]

def unite(a, b):
    root_a = find_root(a)
    parent[a] = root_a
    root_b = find_root(b)
    parent[b] = root_b
    if root_a != root_b:
        parent[root_b] = root_a

def find_root(a):
    ls = []
    while parent[a] != a:
        ls.append(a)
        a = parent[a]
    for l in ls:
        parent[l] = a
    return a


for i in range(m):
    x, y, z = [int(i) for i in sys.stdin.readline().split()]
    x -= 1
    y -= 1
    unite(x, y)

_set = set()
for i in range(n):
    _set.add(find_root(i))
print(len(_set))