Connect cities

from collections import defaultdict, deque

n, m = [int(x) for x in input().split()]

graph = defaultdict(list)
for _ in range(m):
    a, b = [int(x) for x in input().split()]
    graph[a].append(b)
    graph[b].append(a)

visited = [False] * (n + 1)
roads = []

def bfs(start):
    visited[start] = True
    queue = deque([start])
    while queue:
        node = queue.popleft()
        for neighbor in graph[node]:
            if not visited[neighbor]:
                visited[neighbor] = True
                queue.append(neighbor)

for city in range(1, n + 1):
    if not visited[city]:
        print(city)
        roads.append(city)
        bfs(city)

k = len(roads) - 1
print(k)

for i in range(k):
    print(roads[i], roads[i + 1])

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER