5 5
1 2
1 3
2 4
3 4
4 5

1 2 4 5

from collections import deque
n,m=map(int,input().split())
graph=[[] for _ in range(n+1)]
for _ in range(m):
    u,v=map(int,input().split())
    graph[u].append(v); graph[v].append(u)
prev=[-1]*(n+1); visited=[False]*(n+1)
q=deque([1]); visited[1]=True
while q:
    node=q.popleft()
    for nxt in graph[node]:
        if not visited[nxt]:
            visited[nxt]=True; prev[nxt]=node; q.append(nxt)
if not visited[n]: print('NONE')
else:
    path=[]
    cur=n
    while cur!=-1: path.append(cur); cur=prev[cur]
    print(*path[::-1])