//
//  main.cpp
//  berarii2
//
//  Created by Ciprian Ionescu on 11/28/19.
//  Copyright © 2019 Ciprian Ionescu. All rights reserved.
//

#include <iostream>
#include <fstream>
#include <array>
#define MAX_N 16001
#define MAX_M 32002
#define INF 16000001

int v[MAX_N], smax = -INF;

class Graph {
public:
    void add(int x, int y) {
        nodes[++size].node = y;
        nodes[size].next = list[x];
        list[x] = &nodes[size];
    }
    
    int asmax(int x);
private:
    size_t size;
    
    struct node {
        int node;
        struct node* next;
    };
    
    std::array<node, MAX_M> nodes;
    std::array<node*, MAX_N> list;
    
    std::array<bool, MAX_N> visited;
};

int Graph::asmax(int x) {
    visited[x] = true;
    
    node* p = list[x];
    int y, d, s;
    
    s = v[x];
    while (p) {
        y = p->node;
        if (!visited[y]) if ((d = asmax(y)) >= 0) s += d;
        p = p->next;
    }
    
    if (s > smax) smax = s;
    
    return s;
}

Graph g;

std::ifstream fin("asmax.in");
std::ofstream fout("asmax.out");

int main(int argc, const char * argv[]) {
    int x, y, n;
    // Graph g;
    fin >> n;
    
    for (int i = 1 ; i <= n ; i++) fin >> v[i];
    for (int i = 1 ; i < n ; i++) {
        fin >> x >> y;
        g.add(x, y);
        g.add(y, x);
    }
    
    g.asmax(1);
    
    fout << smax;
    return 0;
}