9253: ABC293 —— Ex - Optimal Path Decomposition
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Description
### Problem Statement
You are given a tree with $N$ vertices numbered $1$ through $N$. The $i$-th edge connects vertex $A_i$ and vertex $B_i$.
Find the minimum integer $K$ such that you can paint each vertex in a color so that the following two conditions are satisfied. You may use any number of colors.
- For each color, the set of vertices painted in the color is connected and forms a simple path.
- For all simple paths on the tree, there are at most $K$ distinct colors of the vertices in the path.
You are given a tree with $N$ vertices numbered $1$ through $N$. The $i$-th edge connects vertex $A_i$ and vertex $B_i$.
Find the minimum integer $K$ such that you can paint each vertex in a color so that the following two conditions are satisfied. You may use any number of colors.
- For each color, the set of vertices painted in the color is connected and forms a simple path.
- For all simple paths on the tree, there are at most $K$ distinct colors of the vertices in the path.
Input
### Input
The input is given from Standard Input in the following format:
```
$N$
$A_1$ $B_1$
$\vdots$
$A_{N-1}$ $B_{N-1}$
```
The input is given from Standard Input in the following format:
```
$N$
$A_1$ $B_1$
$\vdots$
$A_{N-1}$ $B_{N-1}$
```
Output
### Output
Print the answer.
Print the answer.
Constraints
### Constraints
- $1 \leq N \leq 2 \times 10^5$
- $1 \leq A_i, B_i \leq N$
- The given graph is a tree.
- All values in the input are integers.
- $1 \leq N \leq 2 \times 10^5$
- $1 \leq A_i, B_i \leq N$
- The given graph is a tree.
- All values in the input are integers.
Sample 1 Input
7
3 4
1 5
4 5
1 2
7 4
1 6
Sample 1 Output
3
If K=3, the conditions can be satisfied by painting vertices 1,2,3,4, and 5 in color 1, vertex 6 in color 2, and vertex 7 in color 3. If K≤2, there is no way to paint the vertices to satisfy the conditions, so the answer is 3.
Sample 2 Input
6
3 5
6 4
6 3
4 2
1 5
Sample 2 Output
1
Sample 3 Input
9
1 3
9 5
8 7
2 1
5 2
5 8
4 8
6 1
Sample 3 Output
3