import java.util.*;

public class Main {
    static ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
    static int[] ord;
    static int[] lowLink;
    static int count = 0;
    
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		for (int i = 0; i < n; i++) {
		    graph.add(new ArrayList<>());
		}
		int[] lefts = new int[n];
		int[] rights = new int[n];
		for (int i = 0; i < n; i++) {
		    int a = sc.nextInt() - 1;
		    int b = sc.nextInt() - 1;
		    graph.get(a).add(b);
		    graph.get(b).add(a);
		    lefts[i] = a;
		    rights[i] = b;
		}
		ord = new int[n];
		lowLink = new int[n];
		search(0, 0);
		ArrayList<Integer> ans = new ArrayList<>();
		for (int i = 0; i < n; i++) {
		    if ((ord[lefts[i]] < ord[rights[i]] && ord[lefts[i]] >= lowLink[rights[i]]) ||
		       (ord[lefts[i]] > ord[rights[i]] && lowLink[lefts[i]] <= ord[rights[i]])) {
		        ans.add(i + 1);
		    }
		}
		StringBuilder sb = new StringBuilder();
		Collections.sort(ans);
		sb.append(ans.size()).append("\n");
		for (int i = 0; i < ans.size(); i++) {
		    if (i > 0) {
		        sb.append(" ");
		    }
		    sb.append(ans.get(i));
		}
		System.out.println(sb);
   }
   
   static int search(int idx, int from) {
       if (ord[idx] > 0) {
           return ord[idx];
       }
       count++;
       ord[idx] = count;
       lowLink[idx] = count;
       for (int x : graph.get(idx)) {
           if (x == from) {
               continue;
           }
           lowLink[idx] = Math.min(lowLink[idx], search(x, idx));
       }
       return lowLink[idx];
   }
}