Mashmokh and Water Tanks

题意翻译

给你一棵树，k升水，p块钱，进行一次游戏。 在游戏进行前，可以在任意个节点上放置1升水（总数不超过k） 游戏进行若干轮，每轮游戏开放所有节点，可以选择若干个节点关闭，代价为该节点的水数量。然后所有未关闭的节点的水流向它的父亲(不会连续移动)。 最后，根节点中的水会被取走，水的数量为该轮游戏的盈利。 求盈利最大的某轮游戏的盈利。

题目描述

Mashmokh is playing a new game. In the beginning he has $ k $ liters of water and $ p $ coins. Additionally he has a rooted tree (an undirected connected acyclic graph) that consists of $ m $ vertices. Each vertex of the tree contains a water tank that is empty in the beginning. The game begins with the fact that Mashmokh chooses some (no more than $ k $ ) of these tanks (except the root) and pours into each of them exactly $ 1 $ liter of water. Then the following process is performed until there is no water remained in tanks. - The process consists of several steps. - At the beginning of each step Mashmokh opens doors of all tanks. Then Mashmokh closes doors of some tanks (he is not allowed to close door of tank in the root) for the duration of this move. Let's denote the number of liters in some tank with closed door as $ w $ , Mashmokh pays $ w $ coins for the closing of that tank during this move. - Let's denote by $ x_{1},x_{2},...,x_{m} $ as the list of vertices of the tree sorted (nondecreasing) by their depth. The vertices from this list should be considered one by one in the order. Firstly vertex $ x_{1} $ (which is the root itself) is emptied. Then for each vertex $ x_{i} $ $ (i>1) $ , if its door is closed then skip the vertex else move all the water from the tank of vertex $ x_{i} $ to the tank of its father (even if the tank of the father is closed). Suppose $ l $ moves were made until the tree became empty. Let's denote the amount of water inside the tank of the root after the $ i $ -th move by $ w_{i} $ then Mashmokh will win $ max(w_{1},w_{2},...,w_{l}) $ dollars. Mashmokh wanted to know what is the maximum amount of dollars he can win by playing the above game. He asked you to find this value for him.

输入输出格式

输入格式

The first line of the input contains three space-separated integers $ m,k,p (2<=m<=10^{5}; 0<=k,p<=10^{9}) $ . Each of the following $ m-1 $ lines contains two space-separated integers $ a_{i},b_{i} (1<=a_{i},b_{i}<=m; a_{i}≠b_{i}) $ — the edges of the tree. Consider that the vertices of the tree are numbered from 1 to $ m $ . The root of the tree has number 1.

输出格式

Output a single integer, the number Mashmokh asked you to find.

输入输出样例

输入样例 #1

10 2 1
1 2
1 3
3 4
3 5
2 6
6 8
6 7
9 8
8 10

输出样例 #1

2

输入样例 #2

5 1000 1000
1 2
1 3
3 4
3 5

输出样例 #2

4

说明

The tree in the first sample is shown on the picture below. The black, red, blue colors correspond to vertices with 0, 1, 2 liters of water. One way to achieve the maximum amount of money is to put 1 liter of water in each of vertices 3 and 4. The beginning state is shown on the picture below. Then in the first move Mashmokh will pay one token to close the door of the third vertex tank. The tree after the first move is shown on the picture below. After the second move there are 2 liters of water in the root as shown on the picture below. 

题意翻译

给你一棵树，k升水，p块钱，进行一次游戏。 在游戏进行前，可以在任意个节点上放置1升水（总数不超过k） 游戏进行若干轮，每轮游戏开放所有节点，可以选择若干个节点关闭，代价为该节点的水数量。然后所有未关闭的节点的水流向它的父亲(不会连续移动)。 最后，根节点中的水会被取走，水的数量为该轮游戏的盈利。 求盈利最大的某轮游戏的盈利。