using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string[] input = Console.ReadLine().Split(' ');

        int n = int.Parse(input[0]);

        int m = int.Parse(input[1]);

        var vertices = new List<int>[n];

        var edges = new int[m][];

        //Initialize vertices and edges

        for(int i = 0; i < m; i++)

        {

            input = Console.ReadLine().Split(' ');

            for(int j = 0; j < 2; j++)

            {

                int vertex = int.Parse(input[j]);

                if(vertices[vertex] == null)

                {

                    vertices[vertex] = new List<int>{i};

                }

                else

                {

                    vertices[vertex].Add(i);

                }

                edges[i][j] = vertex;

            }

        }

        var result = new List<int>();

        //Loop through edges and find solutions

        for(int i = 0; i < m; i++)

        {

            if(IsSolution(vertices, edges, i))

            {

                result.Add(i);

            }

        }

        foreach(var id in result)

        {

            Console.Write(id + " ");

        }

    }

    public static bool IsSolution(List<int>[] vertices, int[][] edges, int edge)

    {

        bool isSolution = true;

        int currentEdge = edge;

        int currentVertex = edges[edge][1];

        var figures = new List<int>[2];

        figures[0] = new List<int>{currentVertex};

        bool[] visited = new bool[vertices.Length];

        visited[edges[edge][1]] = true;

        while(true)

        {

            bool found = false;

            for(int i = 0; i < vertices[currentVertex].Count; i++)

            {

                int otherEdge = vertices[currentVertex][i];

                int otherVertex = edges[otherEdge][0] == currentVertex ? edges[otherEdge][1] : edges[otherEdge][0];

                if(!visited[otherVertex])

                {

                    figures[0].Add(otherVertex);

                    visited[otherVertex] = true;

                    currentVertex = otherVertex;

                    found = true;

                    break;

                }           

            }

            if(!found)

            {

            }

        }

        return isSolution;

    }

}