#include <fstream>
#include <vector>
#include <climits>

using namespace std;

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


const int N = 16001;
const long long MIN = LLONG_MIN;

int n;
int v[N];
long long sm[N], em;
vector<int> a[N];
bool viz[N] = {false};

void dfs(const int x)
{
    viz[x] = true;
    sm[x] = v[x];
    int y;
    for(int i = 0; i < a[x].size(); i++)
    {
        y = a[x][i];
        if(viz[y] == false)
        {
            dfs(y);
            sm[x] = max(sm[x], sm[x] + sm[y]);
        }
    }
    em = max(em, sm[x]);
}

int main()
{
    in >> n;
    em = MIN;
    for(int i = 1; i <= n; i++)
    {
        in >> v[i];
        sm[i] = MIN;
    }
    for(int i = 0; i < n - 1; i++)
    {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    out << em << '\n';
    return 0;
}