CSES Problem Set

# Distance Queries

CSES - Distance Queries

 Time limit: 1.00 s Memory limit: 512 MB

You are given a tree that consists of $n$ nodes.

Your task is to process $q$ queries of the form: what is the distance between nodes $a$ and $b$?

Input

The first input line contains two integers $n$ and $q$: the number of nodes and queries. The nodes are numbered $1,2,\ldots,n$.

Then there are $n-1$ lines that describe the edges. Each line contains two integers $a$ and $b$: there is an edge between nodes $a$ and $b$.

Finally, there are $q$ lines that describe the queries. Each line contains two integer $a$ and $b$: what is the distance between nodes $a$ and $b$?

Output

Print $q$ integers: the answer to each query.

Constraints
• $1 \le n, q \le 2 \cdot 10^5$
• $1 \le a,b \le n$
Example

Input:
5 3 1 2 1 3 3 4 3 5 1 3 2 5 1 4

Output:
1 3 2