#include <iostream>
#include <fstream>
#include <vector>
#define nm 16010
using namespace std;

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


int n,m;
vector <int> G[nm];
int index[nm],cost[nm],viz[nm],rez;

void dfs(int nod)
{
    viz[nod]=1;
    cost[nod]=index[nod];

    for(vector <int>::iterator it = G[nod].begin(); it != G[nod].end(); it++)
    {
        if(!viz[*it])
        {
            dfs(*it);
            cost[nod]+=max(cost[*it],0);
        }
    }
}

int main()
{
    int x, y, i;
    for(i = 1; i <=n; i++)
        fin>>index[i];

    for(int i = 1; i <n ; i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    dfs(1);

    rez = -10;

    for(i=1; i<=n; i++)
        if(cost[i]>rez)
            rez=cost[i];
    fout<<rez;
}