#include <bits/stdc++.h>

using namespace std;

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

int N, E[16010], A[16010], a, b;
vector<int>L[16010];
bitset<16010>v;

void DFS(int node)
{
    v[node] = 1;

    for(int i = 0; i < L[node].size(); i ++)
    {
        if(v[ L[node][i] ] == 0)
        {
            DFS(L[node][i]);
        }
    }

    for(int i = 0; i < L[node].size(); i ++)
    {
        E[node] += max(E[ L[node][i] ], 0);
    }

    E[node] += A[node];
}

int main()
{
    fin >> N;

    for(int i = 1; i <= N; i ++)
    {
        fin >> A[i];
    }

    for(int i = 1; i < N; i ++)
    {
        fin >> a >> b;
        L[a].push_back(b);
        L[b].push_back(a);
    }

    DFS(1);

    int solution = INT_MIN;

    for(int i = 1; i <= N; i ++)
    {
        solution = max(solution, E[i]);
    }

    fout << solution;


    return 0;
}