import sys
sys.setrecursionlimit(10**7)
n=int(input())
ab=[list(map(int,input().split())) for _ in range(n)]
g=[[] for _ in range(n)]
for i,(a,b) in enumerate(ab):
  a,b=a-1,b-1
  g[a].append([b,i])
  g[b].append([a,i])
seen=[[None,None] for _ in range(n)]
# seen[i]:[j,v]=[橋jをつかい、島vからきた]
todo=[[0,-1]]
def func(v,p):
  for nv,i in g[v]:
    if nv==p:continue
    if seen[nv][0] is not None:
      ans=1
      ary=[i+1]
      now=v
      while now!=nv:
        i,now=seen[now]
        ary.append(i+1)
        ans+=1
      print(ans)
      print(*ary)
      exit()
    else:
      seen[nv]=[i,v]
      func(nv,v)
      seen[nv]=[None,None]
func(0,-1)