#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int maxn = 16005;
vector <int> a[maxn];
int viz[maxn];
int D[maxn];
void dfs(int nod)
{
    viz[nod] = 1;
    for(auto it : a[nod])
        if(!viz[it])
            dfs(it);
    for(auto it : a[nod])
        D[nod] = max(D[nod], D[nod] + D[it]);
}

int main()
{
    int n;
    in >> n;
    for(int i = 1; i <= n; i++)
        in >> D[i];
    for(int i = 1; i <= n - 1; i++)
    {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    int mx = -(1 << 30);
    for(int i = 1; i <= n; i++)
        mx = max(mx, D[i]);
    out << mx;
    return 0;
}