#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <vector>
using namespace std;

const int N = (int)1e5 + 10;

struct Edge
{
	int to, ind;
	Edge () {}
	Edge (int to, int ind) : to(to), ind(ind) {}
};
vector <Edge> g[N];
vector <int> ans;
int tin[N];
int d[N];
bool used[N];
int tme = 0;

void dfs(int v, int par = -1)
{
	used[v] = 1;
	tin[v] = tme++;
	d[v] = tin[v];
	bool isPar = false;
	int cntChild = 0;
	int minVal = (int)1e9;
	for (int i = 0; i < (int)g[v].size(); i++)
	{
		int to = g[v][i].to;
		if (!used[to])
		{
			cntChild++;
			dfs(to, v);
			d[v] = min(d[v], d[to]);
			minVal = min(minVal, d[to]);
		}
		else
		{
			if ((to == par && isPar) || to != par)
			{
				d[v] = min(d[v], tin[to]);
			}
			if (to == par)
				isPar = true;
		}
	}
	if (par == -1 && cntChild > 1)
		ans.push_back(v);
	else if (par != -1 && minVal >= tin[v])
		ans.push_back(v);
}

int main()
{

	int n, m;
	scanf("%d%d", &n, &m);

	for (int i = 0; i < m; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		g[a].push_back(Edge(b, i + 1));
		g[b].push_back(Edge(a, i + 1));
	}

	for (int i = 1; i <= n; i++)
	{
		if (!used[i])
			dfs(i);
	}
	sort(ans.begin(), ans.end());
	printf("%d\n", (int)ans.size());
	for (int i = 0; i < (int)ans.size(); i++)
		printf("%d ", ans[i]);

	return 0;
}
/*
9 12
1 2 1 3

*/