B"You are given a tree with n vertices numbered from 1 to n . The height of the i -th vertex is h_i . You can place any number of towers into vertices, for each tower you can choose which vertex to put it in, as well as choose its efficiency. Setting up a tower with efficiency e costs e coins, where e > 0 . It is considered that a vertex x gets a signal if for some pair of towers at the vertices u and v ( u neq v , but it is allowed that x = u or x = v ) with efficiencies e_u and e_v , respectively, it is satisfied that min(e_u, e_v) geq h_x and x lies on the path between u and v . Find the minimum number of coins required to set up towers so that you can get a signal at all vertices. The first line contains an integer n ( 2 <= n <= 200 ,000 ) -- the number of vertices in the tree. The second line contains n integers h_i ( 1 <= h_i <= 10^9 ) -- the heights of the vertices. Each of the next n - 1 lines contain a pair of numbers v_i, u_i ( 1 <= v_i, u_i <= n ) -- an edge of the tree. It is guaranteed that the given edges form a tree. Print one integer -- the minimum required number of coins. In the first test case it's optimal to install two towers with efficiencies 2 at vertices 1 and 3 . In the second test case it's optimal to install a tower with efficiency 1 at vertex 1 and two towers with efficiencies 3 at vertices 2 and 5 . In the third test case it's optimal to install two towers with efficiencies 6 at vertices 1 and 2 . "...