#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

#define N 16005

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

int n, mx = -(1 << 30);
vector <int> v, a[N], d(N);
vector <bool> viz(N);

void dfs(int x)
{
    viz[x] = 1;
    d[x] = v[x];
    for(int i=0; i<a[x].size(); i++)
        if(!viz[a[x][i]])
        {
            dfs(a[x][i]);
            if(d[a[x][i]] > 0)
                d[x] += d[a[x][i]];
        }
    if(mx < d[x])
        mx = d[x];
}

int main()
{
    fin>>n;
    int x, y;
    v.push_back(0);
    for(int i=1; i<=n; i++)
    {
        fin>>x;
        v.push_back(x);
    }
    for(int i=1; i<n; i++)
    {
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    dfs(1);
    fout<<mx;

    return 0;
}