#include <fstream>
#include <vector>


using namespace std;

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

const int N = 16000;

vector<int> a[N+5];
int n, val[N+5], viz[N+5], s[N+5];
int sol=-1000;

void dfs(int x)
{
    viz[x] = 1;
    s[x] = val[x];
    for (auto i:a[x])
    {
        if (!viz[i])
        {
            dfs(i);
            if (s[i]>0)
            {
                s[x]+=s[i];
            }
        }
    }

    sol = max(sol,s[x]);
}

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