백준 13023번: ABCDE

https://www.acmicpc.net/problem/13023

13023번: ABCDE

import sys
sys.setrecursionlimit(10000)
input = sys.stdin.readline
n,m = map(int, input().split())
arrive = False
a = [[] for _ in range(n+1)]
visited = [False]*(n+1)
 
def DFS(now, depth):
    global arrive
    if depth == 5:
        arrive = True
        return
    visited[now] = True
    for i in a[now]:
        if not visited[i]:
            DFS(i,depth+1)
    visited[now] = False
 
for _ in range(m):
    s,e = map(int, input().split())
    a[s].append(e)
    a[e].append(s)
 
for i in range(n):
    DFS(i,1)
    if arrive:
        break
if arrive:
    print(1)
else:
    print(0)