#include<stdio.h>
using namespace std;
int val[16005], vf[32005], lst[32005], urm[32005], m, viz[16005], sum[16005], max = -1;
void adaugare (int x, int y)
{
    m++;
    vf[m] = y;
    urm[m] = lst[x];
    lst[x] = m;
}
void dfs(int x)
{
    int y, p;
    viz[x] = true;
    p = lst[x];
    sum [x] = val[x];
    while (p != 0)
    {
        y = vf[p];
        if (!viz[y])
        {
            dfs(y);
            if (sum[x] + sum[y] > sum[x])
                sum[x] += sum[y];
        }
        p = urm[p];
    }
    if (sum[x] > max)
        max = sum[x];
}
int main ()
{
    FILE *in ,*out;
    in = fopen ("asmax.in", "r");
    out = fopen ("asmax.out", "w");
    int i,n;
    fscanf (in, "%d", &n);
    for (i = 1; i <= n; i++)
        fscanf(in, "%d", &val[i]);
    int x, y;
    for (i = 1; i <= n - 1; i++)
    {
        fscanf (in, "%d%d", &x, &y);
        adaugare(x, y);
        adaugare(y, x);
    }
    for (i = 1; i <= n; i++)
        dfs(i);
    fprintf (out, "%d", max);
    return 0;
}