from collections import deque,Counter INF=float("inf") n,m=map(int,input().split()) R=[[] for _ in range(n+1)] for _ in range(m): u,v=map(int,input().split()) R[u].append(v) R[v].append(u) que=deque() que.append(1) F=[INF]*(n+1) F[1]=0 while que: c=que.popleft() for i in R[c]: if F[c]+1