#include <bits/stdc++.h>
using namespace std;
const int nmax = 16005;
vector<int> g[nmax];
int n, val[nmax];
bool viz[nmax];

void dfs(int dad)
{
    int i, son;
    viz[dad]=true;
    for(i=0; i<g[dad].size(); i++)
    {
        son=g[dad][i];
        if(viz[son]==false)
        {
            dfs(son);
            if(val[son]>0) val[dad]+=val[son];
        }
    }
}

int main()
{
    freopen ("asmax.in", "r", stdin);
    freopen ("asmax.out", "w", stdout);
    int i, n, x, y, sol=-0x3f3f3f3f;
    scanf("%d ", &n);
    for(i=1; i<=n; i++)
        scanf("%d ", &val[i]);
    for(i=1; i<n; i++)
    {
        scanf ("%d %d\n", &x, &y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    for (i=1; i<=n; i++)
        if (val[i]>sol)
            sol=val[i];
    printf ("%d\n", sol);
    fclose(stdin);
    fclose(stdout);
    return 0;
}