Grass Planting
时间限制:C/C++/Rust/Pascal 1秒,其他语言2秒
空间限制:C/C++/Rust/Pascal 32 M,其他语言64 M
64bit IO Format: %lld

题目描述

Farmer John has N barren pastures (2 <= N <= 100,000) connected by N-1  bidirectional roads, such that there is exactly one path between any two  pastures.  Bessie, a cow who loves her grazing time, often complains about  how there is no grass on the roads between pastures.  Farmer John loves  Bessie very much, and today he is finally going to plant grass on the roads.  He will do so using a procedure consisting of M steps (1 <= M <= 100,000).
At each step one of two things will happen:
- FJ will choose two pastures, and plant a patch of grass along each road in between the two pastures, or,
- Bessie will ask about how many patches of grass on a particular road, and  Farmer John must answer her question.
Farmer John is a very poor counter -- help him answer Bessie's questions!

输入描述:

* Line 1: Two space-separated integers N and M
* Lines 2..N: Two space-separated integers describing the endpoints of a road.
* Lines N+1..N+M: Line i+1 describes step i. The first character of the line is either P or Q, which describes whether or not FJ is planting grass or simply querying. This is followed by two space-separated integers Ai and Bi (1 <= Ai, Bi <= N) which describe FJ's action or query.

输出描述:

* Lines 1..???: Each line has the answer to a query, appearing in the
same order as the queries appear in the input.
示例1

输入

复制
4 6
1 4
2 4
3 4
P 2 3
P 1 3
Q 3 4
P 1 4
Q 2 4
Q 1 4

输出

复制
2
1
2