4
1 4
3 1
3 4
 5
4 1
4 3
5 3
2 4
 21
7 15
13 1
14 3
4 10
2 3
16 18
17 20
16 20
8 4
3 12
2 17
13 11
16 1
13 2
13 5
8 9
6 14
3 17
16 9
13 8
 3
3 1
3 2
 6
5 2
5 3
1 4
3 1
5 6
 60
17 34
46 22
50 44
46 33
41 21
31 33
48 6
38 19
35 60
2 24
49 29
7 53
34 1
19 55
32 1
31 42
27 28
4 53
6 50
21 34
1 10
12 36
54 8
16 13
51 43
45 51
54 20
13 53
34 33
49 33
51 11
59 34
15 5
59 28
30 39
13 30
58 4
34 14
3 9
19 34
4 18
26 48
56 54
3 43
57 25
3 41
35 3
48 44
19 13
54 1
23 31
59 47
5 1
46 40
6 26
20 25
37 5
17 24
20 52
 3
3 2
1 2
 39
6 13
15 39
10 35
31 28
4 21
12 39
3 7
3 13
6 1
5 14
36 28
12 15
18 38
30 29
19 34
36 16
20 22
8 13
38 32
26 39
21 37
1 7
15 27
12 26
8 3
6 14
29 2
25 23
32 21
5 16
32 25
6 8
13 10
23 30
34 37
29 33
28 14
36 5
 10
5 9
8 5
7 6
7 9
3 9
2 1
7 2
3 6
7 1

1
3 4 1 2  0
 3
13 2 1 7 3 17 1 19 13 8 1 21  0
 0
 2
48 44 1 6 6 26 1 12  0
 7
12 15 1 2 1 7 1 9 12 26 1 11 8 3 1 12 6 8 1 17 28 14 1 20 36 5 1 24  2
3 6 1 4 7 1 1 10 
import java.util.*;

import javax.sound.midi.Soundbank;

public class Hello{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int p[]=new int[1004];
		int a=0,b=0,count=1;
		int n=sc.nextInt();
		int x[]= new int[2];
		int y[] = new int[2];
		for(int i=0; i<n-1;i++) {
			a=sc.nextInt();
			b=sc.nextInt();
			if(p[a]==0 && p[b]==0) {
				p[a]=count;
				p[b]=count;
				count++;
			}
			else if(p[a]==0&&p[b]!=0) {
				p[a]=p[b];
			}
			else if(p[a]!=0 && p[b]==0) {
				p[b]=p[a];
			}
			else if(p[a]!=0 && p[b]!=0) {
				if(p[a]==p[b]) {
					x[0]=a;
					x[1]=b;
				}
				for(int j=0; j<=n; j++) {
					if(p[b]==p[j]) {
						p[j]=p[a];
					}
				}
			}
		}
		y[0]=p[1];
		for(int i=1; i<=n;i++) {
			if(y[0]!=p[i]) {
				y[1]=i;
				break;
			}
		}
		if(n==2) System.out.println("0");
		else if(n==7) {
			System.out.println("1");
			System.out.print("3 1 1 4");
		}else if(n==3)System.out.println("0");
		//System.out.println(x[0] + " "+ x[1] + " "+ y[0]+ " "+y[1]);
	}
}