#include <bits/stdc++.h>

#define MAXN 16005

int N, V[MAXN], DP[MAXN], Ans;
std::vector <int> ADC[MAXN];

inline void AddEdge(int X, int Y) {
    ADC[X].push_back(Y);
    ADC[Y].push_back(X);
}

void DFS(int Vertex = 1, int Parent = 0) {
    DP[Vertex] = V[Vertex];
    for (auto Edge:ADC[Vertex])
        if (Edge != Parent)
            DFS(Edge, Vertex), DP[Vertex] = std::max(DP[Vertex], DP[Vertex] + DP[Edge]);
    Ans = std::max(Ans, DP[Vertex]);
}

std::ifstream In ("asmax.in");
std::ofstream Out("asmax.out");

void Citire() {
    In >> N;
    for (int i=1; i<=N; ++i)
        In >> V[i];
    for (int i=1, x, y; i<N; ++i)
        In >> x >> y, AddEdge(x, y);
}

void Rezolvare() {
    DFS();
    Out << Ans << '\n';
}

int main()
{
    Citire();
    Rezolvare();

    return 0;
}