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Crazy Bobo

Time Limit
3s
Memory Limit
65536KB
Judge Program
Standard
Ratio(Solve/Submit)
66.67%(2/3)
Description:

Bobo has a tree,whose vertices are conveniently labeled by 1,2,...,n.Each node has a weight wi. All the weights are distrinct.
A set with m nodes v1,v2,...,vm is a Bobo Set if:
- The subgraph of his tree induced by this set is connected.
- After we sort these nodes in set by their weights in ascending order,we get u1,u2,...,um,(that is,wui<wui+1 for i from 1 to m-1).For any node x in the path from ui to ui+1(excluding ui and ui+1),should satisfy wx<wui.
Your task is to find the maximum size of Bobo Set in a given tree.

Input:

The input consists of several tests. For each tests:
The first line contains a integer n (1n500000). Then following a line contains n integers w1,w2,...,wn (1wi109,all the wi is distrinct).Each of the following n-1 lines contain 2 integers ai and bi,denoting an edge between vertices ai and bi (1ai,bin).
The sum of n is not bigger than 800000.

Output:

For each test output one line contains a integer,denoting the maximum size of Bobo Set.

Sample Input:
7
3 30 350 100 200 300 400
1 2
2 3
3 4
4 5
5 6
6 7
Sample Output:
5
Source:

2015 Multi-University Training Contest 3


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