package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	g := newGraph(n)
	for i := 0; i < n; i++ {
		a := getNextInt(scanner) - 1
		b := getNextInt(scanner) - 1
		g.AppendEdge(a, b, i)
		g.AppendEdge(b, a, i)
	}
	var dfs func(int, int)
	bb := map[int]bool{}
	dfs = func(now, p int) {
		if g.v[now].visit {
			return
		}
		g.v[now].visit = true
		g.v[now].deg = 1
		for _, e := range g.e[now] {
			if e.to == p {
				continue
			}
			if !g.v[e.to].visit {
				dfs(e.to, now)
			}
			if g.v[e.to].deg == 0 {
				bb[e.id] = true
			}
			g.v[now].deg += g.v[e.to].deg
		}
		if g.v[now].deg == 1 {
			g.v[now].deg--
		}
	}
	dfs(0, -1)
	fmt.Fprintln(writer, n-len(bb))
	sep := ""
	for i := 0; i < n; i++ {
		if bb[i] {
			continue
		}
		fmt.Fprintf(writer, "%s%d", sep, i+1)
		sep = " "
	}
	fmt.Fprintln(writer, "")
}

type vertex struct {
	visit bool
	deg   int
}
type edge struct {
	to, id int
}
type graph struct {
	v []vertex
	e [][]edge
}

func newGraph(n int) graph {
	return graph{
		v: make([]vertex, n),
		e: make([][]edge, n),
	}
}
func (g *graph) AppendEdge(from, to, id int) {
	g.e[from] = append(g.e[from], edge{
		to: to,
		id: id,
	})
}