#include <stdio.h>
#include <deque>
#include <vector>

using namespace std;
const int NMAX = 16000, INF = 1e7;

vector<int> edges[NMAX];
int smax[NMAX], leaves[NMAX], val[NMAX], father[NMAX], lvpt;
bool vis[NMAX];
deque<int> dq;

void getLeaves(int node);
void bfs(int leaves[], int &maxcur);

int main()
{
    int n, i, v1, v2, root, maxx;
    FILE *fin = fopen("asmax.in", "r");
    fscanf(fin, "%d", &n);
    for (i = 0; i < n; i++)
        fscanf(fin, "%d", &val[i]);
    for (i = 0; i < n - 1; i++)
    {
        fscanf(fin, "%d%d", &v1, &v2);
        v1--, v2--;
        edges[v1].push_back(v2);
        edges[v2].push_back(v1);
    }
    fclose(fin);
    root = 0;
    father[root] = root;
    getLeaves(root);
    maxx = -INF;
    bfs(leaves, maxx);
    FILE *fout = fopen("asmax.out", "w");
    fprintf(fout, "%d", maxx);
    fclose(fout);

    return 0;
}

void getLeaves(int node)
{
    int i, len = edges[node].size(), nextnode;
    if (len == 1 && father[node] != node)
    {
        leaves[lvpt++] = node;
        return;
    }
    for (i = 0; i < len; i++)
    {
        nextnode = edges[node][i];
        if (father[node] != nextnode)
        {
            father[nextnode] = node;
            getLeaves(nextnode);
        }
    }
}
void bfs(int leaves[], int &maxcur)
{
    int i, node, nextnode, len;
    for (i = 0; i < lvpt; i++)
        dq.push_front(leaves[i]);
    while (!dq.empty())
    {
        node = dq.back();
        dq.pop_back();
        vis[node] = 1;
        len = edges[node].size();
        smax[node] = val[node];
        for (i = 0; i < len; i++)
        {
            nextnode = edges[node][i];
            if (nextnode != father[node])
                    smax[node] += max(smax[nextnode], 0);
        }
        if (smax[node] > maxcur)
            maxcur = smax[node];
        if (!vis[father[node]])
            dq.push_front(father[node]);
    }
}