#include <bits/stdc++.h>
#include <fstream>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
const int NMAX = 16010;
int n;
vector<int> graf[NMAX];
int varfuri[NMAX];
int best[NMAX];
int res = -2147000000;

void dfs(int node, int father)
{
    best[node]+=varfuri[node];
    for(int next:graf[node])
    {
        if(next==father) continue;
        dfs(next, node);
        if(best[next]>0)
            best[node]+=best[next];
    }
    res = max(res, best[node]);
}

int main()
{
    fin>>n;
    for(int i = 1;i<=n;i++) fin>>varfuri[i];
    for(int i = 1;i<n;i++)
    {
        int x, y;
        fin>>x>>y;
        graf[y].push_back(x), graf[x].push_back(y);
    }
    dfs(1,0);
    fout<<res;
    return 0;
}