#include <iostream>
#include <cstring>
#include <vector>

using namespace std;

#define NM 16005
#define PB push_back

vector <int> G[NM], A[NM];
bool viz[NM];
int BEST[NM], V[NM], N;

void df (int nod)
{
    viz[nod] = 1;
    for (int i = 0; i < G[nod].size(); ++i)
    {
        int nnod = G[nod][i];
        if (viz[nnod]) continue;
        A[nod].PB(nnod);
        df (nnod);
    }
}

void get_BEST(int nod)
{
    BEST[nod] = V[nod];

    for (int i = 0; i < A[nod].size(); ++i)
    {
        int nnod = A[nod][i];
        get_BEST(nnod);

        if (BEST[nnod] > 0) BEST[nod] += BEST[nnod];
    }
}

int main()
{
    freopen ("asmax.in", "r", stdin);
    freopen ("asmax.out", "w", stdout);

    scanf ("%d", &N);

    for (int i = 1; i <= N; ++i) scanf ("%d", &V[i]);

    for (int i = 1; i < N; ++i)
    {
        int a, b;
        scanf ("%d %d", &a, &b);
        G[a].PB(b);
        G[b].PB(a);
    }

    df(1);
    get_BEST(1);

    int best = -2000000000;

    for (int i = 1; i <= N; ++i) best = max (best, BEST[i]);

    printf ("%d", best);

    return 0;
}