using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;
using System.Numerics;

public class Solution
{
    private IList<int>[] graph;
    private bool[] visited;
    private int[] visitedTimes;
    private int[] lowVisitedTimes;
    private IList<IList<int>> criticalConnections;
    private int time;

    public IList<IList<int>> CriticalConnections(int n, IList<IList<int>> connections)
    {
        graph = new IList<int>[n];
        visited = new bool[n];
        visitedTimes = new int[n];
        lowVisitedTimes = new int[n];
        criticalConnections = new List<IList<int>>();
        time = 0;

        InitGraph(n, connections);
        DFS(0, -1);

        return criticalConnections;
    }

    private void DFS(int current, int parent)
    {
        visited[current] = true;
        visitedTimes[current] = lowVisitedTimes[current] = time++;

        foreach (var server in graph[current])
        {
            if (server == parent)
            {
                continue;
            }

            if (!visited[server])
            {
                DFS(server, current);
                if (visitedTimes[current] < lowVisitedTimes[server])
                {
                    criticalConnections.Add(new List<int>(2) { current, server });
                }
                else if (visitedTimes[current] > lowVisitedTimes[server])
                {
                    lowVisitedTimes[current] = lowVisitedTimes[server];
                }
            }
            else
            {
                lowVisitedTimes[current] = Math.Min(lowVisitedTimes[current], visitedTimes[server]);
            }
        }
    }

    private void InitGraph(int n, IList<IList<int>> connections)
    {
        for (int i = 0; i < n; i++)
        {
            graph[i] = new List<int>();
        }

        foreach (var connection in connections)
        {
            var a = connection[0];
            var b = connection[1];
            graph[a].Add(b);
            graph[b].Add(a);
        }
    }
}

class MyClass
{
    public static void Solve()
    {
        var N = int.Parse(Console.ReadLine());
        var edges = new List<IList<int>>();
        var dic = new Dictionary<(int, int), int>();
        for (int i = 0; i < N; i++)
        {
            var data = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var A = data[0] - 1;
            var B = data[1] - 1;
            var edge = new List<int>();
            edge.Add(A);
            edge.Add(B);
            edges.Add(edge);
            dic.Add((A, B), i + 1);
            dic.Add((B, A), i + 1);
        }
        var sol = new Solution();
        var pri = sol.CriticalConnections(N, edges);
        var ans = Enumerable.Range(1, N).ToHashSet();
        foreach (var item in pri)
        {
            var A = item[0];
            var B = item[1];
            ans.Remove(dic[(A, B)]);
        }
        Console.WriteLine(ans.Count());
        Console.WriteLine(string.Join(" ", ans));
    }

    public static void Main()
    {
        var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
}