#include <bits/stdc++.h>
using namespace std;

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

int n, top, maxim=INT_MIN;
int v[16005];
vector<int> L[16005];
bool ap[16005];

void dfs(int nod)
{
    ap[nod] = 1;
    for(auto it: L[nod])
    {
        if(!ap[it])
        {
            dfs(it);
            if(v[it] >= 0)
                v[nod] += v[it];
        }
    }
}

int main()
{
    fin>>n;
    for(int i=1; i<=n; i++)
        fin>>v[i];
    for(int i=1; i<n; i++)
    {
        int x,y;
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1);
    for(int i=1; i<=n; i++)
        maxim = max(maxim, v[i]);
    fout<<maxim;
    return 0;
}