P23957 [AtCoder] Coloring Edges on Tree
普及
题目描述

Problem Statement

Given is a tree G with N vertices.
The vertices are numbered 1 through N, and the i-th edge connects Vertex a_i and Vertex b_i.
Consider painting the edges in G with some number of colors.
We want to paint them so that, for each vertex, the colors of the edges incident to that vertex are all different.
Among the colorings satisfying the condition above, construct one that uses the minimum number of colors.

Input

Input is given from Standard Input in the following format:
N
a_1 b_1
a_2 b_2
$\vdots$
a_{N-1} b_{N-1}

Output

Print N lines.
The first line should contain K, the number of colors used.
The $(i+1)-th line (1 \le i \le N-1)$ should contain c_i, the integer representing the color of the i-th edge, where $1 \le c_i \le K$ must hold.
If there are multiple colorings with the minimum number of colors that satisfy the condition, printing any of them will be accepted.

Constraints

  • $2 \le N \le 10^5$
  • $1 \le a_i \lt b_i \le N$
  • All values in input are integers.
  • The given graph is a tree.

Sample Input 1

3
1 2
2 3

Sample Output 1

2
1
2

Sample Input 2

8
1 2
2 3
2 4
2 5
4 7
5 6
6 8

Sample Output 2

4
1
2
3
4
1
1
2

Sample Input 3

6
1 2
1 3
1 4
1 5
1 6

Sample Output 3

5
1
2
3
4
5

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
3 1 2 2 3
样例输出
2 1 2