B"You're given a tree consisting of n nodes. Every node u has a weight a_u . It is guaranteed that there is only one node with minimum weight in the tree. For every node u (except for the node with the minimum weight), it must have a neighbor v such that a_v<a_u . You should construct a tree to minimize the weight w calculated as follows: The first line contains the integer n (2 <= n <= 5 cdot 10^5) , the number of nodes in the tree. The second line contains n space-separated integers a_1, a_2, ldots, a_n (1 <= a_i <= 10^9) , the weights of the nodes. The next n-1 lines, each contains 2 space-separated integers u and v (1 <= u,v <= n) which means there's an edge between u and v . Output one integer, the minimum possible value for w . In the first sample, the tree itself minimizes the value of w . In the second sample, the optimal tree is: "...