#include <fstream>

using namespace std;

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

const int N = 16001;
const int INF = 1001;

int vf[2*N], urm[2*N], lst[N], v[N], nr, x, y;
bool viz[N];

void adauga(int x, int y)
{
    vf[++nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int x)
{
    int s = 0;
    viz[x] = true;
    for(int p = lst[x]; p != 0; p = urm[p])
    {
        int y = vf[p];
        if(!viz[y])
        {
            dfs(y);
            if(v[y] > 0)
                v[x] += v[y];
        }
    }


}

int main()
{
    int n;
    in >> n;
    for(int i = 1; i <= n; i++)
    {
        in >> v[i];
    }
    for(int i = 1; i <= n - 1; i++)
    {
        in >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }
    dfs(1);
    int maxi = v[1];
    for(int i = 1; i <= n; i++)
    {
        maxi = max(maxi, v[i]);
    }
    out << maxi;
    return 0;
}