#include <stdio.h>
#include <algorithm>

const int MAX_N = 16000;
const int MAX_M = MAX_N - 1;

const int INF = 1000 * MAX_N;

struct list;

struct Node
{
    int id;
    list *to;
    Node *next;
};

struct list
{
    int id;
    Node *p;
}lists_pointers[MAX_N];

Node edges[MAX_M * 2];
int n_edges;

struct
{
    int sum;
    int was;
}nodevals[MAX_N];

void add_edge(int x, int y)
{
    edges[n_edges].id = x;
    edges[n_edges].to = &lists_pointers[y];
    edges[n_edges].next = lists_pointers[x].p;

    lists_pointers[x].p = &edges[n_edges];
    n_edges++;
}


int dfs(list *l)
{
    if(l != NULL)
    {
        Node *x = l->p;

        int sum = nodevals[l->id].sum;
        while(x != NULL)
        {
            if(nodevals[x->to->id].was == false)
            {
                nodevals[x->to->id].was = true;
                int a = dfs(x->to);
                if(a > 0)
                    sum += a;
            }
            x = x->next;
        }

        nodevals[l->id].sum = sum;

        return sum;
    }
    else return 0;
}

int main()
{
    FILE *fin = fopen("asmax.in", "r"),
         *fout = fopen("asmax.out", "w");
    int n, m;
    int r;

    fscanf(fin, "%d", &n);

    for(int i = 0; i < n; i++)
    {
        lists_pointers[i].id = i;
        fscanf(fin, "%d", &nodevals[i].sum);
    }

    m = n - 1;
    for (int i = 0; i < m; i++)
    {
        int x, y;
        fscanf(fin, "%d %d", &x, &y);

        add_edge(x - 1, y - 1);
        add_edge(y - 1, x - 1);
    }

    dfs(&lists_pointers[0]);

    r = -INF;
    for(int i = 0; i < n; i++) {
        r = std::max(r, nodevals[i].sum);
        //printf("%d %d\n", i, nodevals[i].sum);
    }
    fprintf(fout, "%d\n", r);

    fclose(fin);
    fclose(fout);
    return 0;
}