10323.py

import sys


def input():
    return sys.stdin.readline().rstrip()


def main():
    def dfs(current_node: int, depth: int) -> bool:
        if depth == 4:
            return True

        is_visited[current_node] = True
        for next_node in connected[current_node]:
            if not is_visited[next_node]:
                if dfs(next_node, depth + 1):
                    return True
        is_visited[current_node] = False
        return False

    n, m = map(int, input().split())
    connected = [[] for node in range(n)]
    for edge in range(m):
        a, b = map(int, input().split())
        connected[a].append(b)
        connected[b].append(a)

    is_visited = [False] * n
    for node in range(n):
        if len(connected[node]):
            if dfs(node, 0):
                res = 1
                break
    else:
        res = 0
    print(res)


if __name__ == '__main__':
    main()