#P3128. [USACO15DEC] Max Flow P

[USACO15DEC] Max Flow P

题目描述

Farmer John has installed a new system of N1N-1 pipes to transport milk between the NN stalls in his barn (2N50,0002 \leq N \leq 50,000), conveniently numbered 1N1 \ldots N. Each pipe connects a pair of stalls, and all stalls are connected to each-other via paths of pipes.

FJ is pumping milk between KK pairs of stalls (1K100,0001 \leq K \leq 100,000). For the iith such pair, you are told two stalls sis_i and tit_i, endpoints of a path along which milk is being pumped at a unit rate. FJ is concerned that some stalls might end up overwhelmed with all the milk being pumped through them, since a stall can serve as a waypoint along many of the KK paths along which milk is being pumped. Please help him determine the maximum amount of milk being pumped through any stall. If milk is being pumped along a path from sis_i to tit_i, then it counts as being pumped through the endpoint stalls sis_i and tit_i, as well as through every stall along the path between them.

输入格式

The first line of the input contains NN and KK.

The next N1N-1 lines each contain two integers xx and yy (xyx \ne y) describing a pipe between stalls xx and yy.

The next KK lines each contain two integers ss and tt describing the endpoint stalls of a path through which milk is being pumped.

输出格式

An integer specifying the maximum amount of milk pumped through any stall in the barn.

5 10
3 4
1 5
4 2
5 4
5 4
5 4
3 5
4 3
4 3
1 3
3 5
5 4
1 5
3 4
9

提示

2N5×104,1K1052 \le N \le 5 \times 10^4,1 \le K \le 10^5