Buggy python submission (verdict: Runtime Error):
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rank[rx] < rank[ry]:
        pair[rx] = ry
    else:
        pair[ry] = rx
        if rx == ry:
            rank[rx] += 1

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

for i in range(M):
    x, y, z = map(int, input().split())
    unite(x, y)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))


Fixed submission:
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx > ry:
        pair[rx] = pair[ry]
    else:
        pair[ry] = pair[rx]

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

tmp = []
for i in range(M):
    tmp.append(list(map(int, input().split())))
tmp.sort()
for i in range(M):
    x, y = tmp[i][0], tmp[i][1]
    if x < y:
        unite(x, y)
    else:
        unite(y, x)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))

Buggy python submission (verdict: Runtime Error):
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rank[rx] < rank[ry]:
        pair[rx] = ry
    else:
        pair[ry] = rx
        if rx == ry:
            rank[rx] += 1

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

for i in range(M):
    x, y, z = map(int, input().split())
    unite(x, y)

cnt = set()
for k, y in pair.items():
    ry = root(y)
    cnt.add(ry)
print(len(cnt))


Fixed submission:
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx > ry:
        pair[rx] = pair[ry]
    else:
        pair[ry] = pair[rx]

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

tmp = []
for i in range(M):
    tmp.append(list(map(int, input().split())))
tmp.sort()
for i in range(M):
    x, y = tmp[i][0], tmp[i][1]
    if x < y:
        unite(x, y)
    else:
        unite(y, x)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))

Buggy python submission (verdict: Runtime Error):
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rank[rx] < rank[ry]:
        pair[rx] = ry
    else:
        pair[ry] = x
        if rx == ry:
            rank[x] += 1

def same(x, y):
    rx = root(x)
    ry = root(y)
    return rx == ry

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

for i in range(M):
    x, y, z = map(int, input().split())
    unite(x, y)

cnt = set()
for k, y in pair.items():
    ry = root(y)
    cnt.add(ry)
print(len(cnt))


Fixed submission:
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx > ry:
        pair[rx] = pair[ry]
    else:
        pair[ry] = pair[rx]

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

tmp = []
for i in range(M):
    tmp.append(list(map(int, input().split())))
tmp.sort()
for i in range(M):
    x, y = tmp[i][0], tmp[i][1]
    if x < y:
        unite(x, y)
    else:
        unite(y, x)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))

Buggy python submission (verdict: Runtime Error):
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx == ry:
        return True
    else:
        pair[rx] = ry

def same(x, y):
    rx = root(x)
    ry = root(y)
    return rx == ry

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(M):
    x, y, z = map(int, input().split())
    unite(x, y)

cnt = set()
for k, y in pair.items():
    ry = root(y)
    cnt.add(ry)
print(len(cnt))


Fixed submission:
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx > ry:
        pair[rx] = pair[ry]
    else:
        pair[ry] = pair[rx]

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

tmp = []
for i in range(M):
    tmp.append(list(map(int, input().split())))
tmp.sort()
for i in range(M):
    x, y = tmp[i][0], tmp[i][1]
    if x < y:
        unite(x, y)
    else:
        unite(y, x)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))

Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
pair = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx == ry:
        return True
    else:
        pair[rx] = ry

def same(x, y):
    rx = root(x)
    ry = root(y)
    return rx == ry

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(M):
    x, y, z = map(int, input().split())
    unite(x, y)

cnt = set()
for k, y in pair.items():
    ry = root(y)
    cnt.add(ry)
print(len(cnt))


Fixed submission:
import sys

input = sys.stdin.readline
N, M = map(int, input().split())
pair = {}
rank = {}
def root(x):
    if x == pair[x]:
        return x
    else:
        pair[x] = root(pair[x])
    return pair[x]

def unite(x, y):
    rx = root(x)
    ry = root(y)
    if rx > ry:
        pair[rx] = pair[ry]
    else:
        pair[ry] = pair[rx]

for i in range(1, N+1):
    pair.setdefault(i, i)

for i in range(1, N+1):
    rank.setdefault(i, 0)

tmp = []
for i in range(M):
    tmp.append(list(map(int, input().split())))
tmp.sort()
for i in range(M):
    x, y = tmp[i][0], tmp[i][1]
    if x < y:
        unite(x, y)
    else:
        unite(y, x)

cnt = set()
for k, y in pair.items():
    y = root(y)
    cnt.add(y)
print(len(cnt))