prettified modules

from typing import Dict, List


def dfs(vertex: int, grapg: Dict[int, set], visited: List[bool]):
    visited[vertex] = True
    for near in grapg[vertex]:
        if not visited[near]:
            dfs(near, grapg, visited)


with open("input.txt", "r") as f:
    n, m = map(int, f.readline().split())
    graph = {}

    for i in range(1, n + 1):
        graph[i] = set({})

    line = list(map(int, f.readline().split()))
    if m == 0:
        pass
    elif len(line) > 2:
        for i in range(m):
            graph[line[2 * i]].add(line[2 * i + 1])
            graph[line[2 * i + 1]].add(line[2 * i])
    else:
        graph[line[0]].add(line[1])
        graph[line[1]].add(line[0])
        for i in range(m - 1):
            leaf_1, leaf_2 = map(int, f.readline().split())
            graph[leaf_1].add(leaf_2)
            graph[leaf_2].add(leaf_1)

visited = [False] * (n + 1)
count = 0

for i in range(1, n + 1):
    if not visited[i]:
        dfs(i, graph, visited)
        count += 1

with open("output.txt", "w") as f:
    f.write(str(count))