CSES - Distance Queries

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Gửi bài giải

Điểm: 1,00 (OI)
Giới hạn thời gian: 1.0s
Giới hạn bộ nhớ: 512M
Input: stdin
Output: stdout

Nguồn bài:
https://cses.fi/problemset/task/1135
Dạng bài
Ngôn ngữ cho phép
C, C++, Java, Kotlin, Pascal, PyPy, Python, Scratch

You are given a tree consisting 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 describing the edges. Each line contains two integers ~a~ and ~b~: there is an edge between nodes ~a~ and ~b~.

Finally, there are ~q~ lines describing 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

Example Output

1
3
2

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