import sys
input = sys.stdin.readline
from collections import deque
class UnDirectedGraph:
  def __init__(self, N):
    self.V = N
    self.edge = [[] for _ in range(self.V)]
    self.edges = [0]*N
    self.visited = [False]*N
    self.parent = [N]*N
    self.order = [N]*N
    self.low = [N]*N
  
  def add_edges(self, M):
    for i in range(M):
      a,b = map(int, input().split())
      self.edge[a-1].append((b-1,i))
      self.edge[b-1].append((a-1,i))
      self.edges[i] = (a-1,b-1)

  def add_edge(self, a, b):
    self.edge[a].append(b)
    self.edge[b].append(a)

  def low_link(self, start):
    stack = deque([start])
    self.parent[start] = -1
    #記録したい値の配列を定義
    self.order[start] = 0
    cnt = 1
    while stack:
      v = stack[-1]
      for u,i in self.edge[v]:
        if u==self.parent[v]:
          pass
        elif self.order[u]<self.order[v]:
          self.low[v] = min(self.low[v], self.order[u])
        elif self.parent[u]==N: #行き
          self.parent[u] = v
          self.order[u] = cnt
          self.low[u] = cnt
          stack.append(u)
          cnt += 1
          break
        else:
          self.low[v] = min(self.low[v], self.low[u])
      else:
        stack.pop() #帰り
    return

N = int(input())
G = UnDirectedGraph(N)
G.add_edges(N)
G.dfs(0)
ans = []
for i,(a,b) in enumerate(G.edges):
  if G.order[a]>G.order[b]:
    a,b = b,a
  if G.low[b]<=G.order[a]:
    ans.append(i+1)
print(len(ans))
print(*ans)