#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int maxn = 16005;
vector <int> v[maxn];
int val[maxn];
int dp[maxn];

void dfs(int nod, int tata)
{
    for(auto it : v[nod])
        if(it != tata)
            dfs(it, nod);
    /*
    int s = 0;
    int mx = -(1 << 30);
    for(auto it : v[nod])
    {
        if(it != tata)
        {
            mx = max(mx, it);
            if(dp[it] > 0)
                s += dp[it];
        }
    }
    if(s == 0)
        s = mx;
    */
    for(auto it : v[nod])
        if(it != tata)
            dp[nod] = max(dp[nod], dp[nod] + dp[it]);
}

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