#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
#define DIM 16005

using namespace std;

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

int n, v[DIM], maxi = -INF;
vector <int> edges[DIM];
bitset <DIM> used;

void dfs(int nod)
{
    used[nod] = 1;
    for(auto child : edges[nod])
        if(!used[child])
        {
            dfs(child);
            v[nod] = max(v[nod], v[nod] + v[child]);
        }
    maxi = max(maxi, v[nod]);
}

int main()
{
    f >> n;
    for(int i = 1; i <= n; i++)
        f >> v[i];

    for(int i = 1; i < n; i++)
    {
        int x, y;
        f >> x >> y;
        edges[x].push_back(y);
        edges[y].push_back(x);
    }

    dfs(1);

    g << maxi;
    return 0;
}