#include <fstream>
#include <vector>
using namespace std;

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

const int oo = 10000;
const int NMAX = 16009;
int n, x, y, maxim = -oo, sum[NMAX];
vector <int> v[NMAX];
vector <int> a;

inline void read_Data() {
    f >> n;
    a.push_back(0);
    for(int i = 1; i <= n; ++i) f >> x, a.push_back(x);
    for(int i = 1; i <= n - 1; ++i) {
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

inline void init() {
    for(int i = 1; i <= n; ++i) sum[i] = -oo;
}

void DFS(int nod) {
    sum[nod] = a[nod];
    int vecin;
    for(int i = 0 ; i < v[nod].size(); ++i) {
        vecin = v[nod][i];
        if(sum[vecin] == -oo) {
            DFS(vecin);
            if(sum[vecin] + sum[nod] > sum[nod]) sum[nod] += sum[vecin];
        }
    }
    if(maxim < sum[nod]) maxim = sum[nod];
}

int main() {
    read_Data();
    init();
    DFS(1);

    g << maxim << '\n';

    g.close();
    f.close();
    return 0;
}