#include <fstream>
#include <vector>
using namespace std;
ifstream cin("asmax.in");
ofstream cout("asmax.out");
const int DIM = 16001;
int t[DIM], d[DIM], val[DIM], viz[DIM];
int n, maxi = -1;
vector<int> a[DIM];
void dfs(int nod);
int main()
{
    cin >> n;
    for(int i = 1; i <= n; ++i)
    {
        cin >> val[i];
    }
    for(int i = 1; i < n; ++i)
    {
        int x, y;
        cin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    dfs(1);
    cout << maxi << '\n';
    return 0;
}

void dfs(int nod)
{
    d[nod] = val[nod];
    viz[nod] = 1;
    for(int i = 0; i < a[nod].size(); ++i)
    {
        if(!viz[a[nod][i]])
        {
            dfs(a[nod][i]);
            if(d[a[nod][i]] > 0)
                d[nod] += d[a[nod][i]];
        }
    }
    if(d[nod] > maxi)
        maxi = d[nod];
}