#P3128. [USACO15DEC] Max Flow P
[USACO15DEC] Max Flow P
题目描述
Farmer John has installed a new system of pipes to transport milk between the stalls in his barn (), conveniently numbered . Each pipe connects a pair of stalls, and all stalls are connected to each-other via paths of pipes.
FJ is pumping milk between pairs of stalls (). For the th such pair, you are told two stalls and , 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 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 to , then it counts as being pumped through the endpoint stalls and , as well as through every stall along the path between them.
输入格式
The first line of the input contains and .
The next lines each contain two integers and () describing a pipe between stalls and .
The next lines each contain two integers and 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
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