2606 바이러스

https://www.acmicpc.net/problem/2606

2606번: 바이러스

n = int(input())
m = int(input())

graph = [[ ]for _ in range(n+1)]
for _ in range(m):
    a, b = map(int, input().split())
    graph[a].append(b)
    graph[b].append(a)

visited = [0]*(n+1)

def dfs (graph,v,visited):
    visited[v]=1
    for i in graph[v]:
        if visited[i]==0:
            dfs(graph,i,visited)
    return True

dfs(graph,1,visited)
print(sum(visited)-1)

어려어~~~~~ 😭😭😭😭😭😭😭😭😭