#include <bits/stdc++.h>
#define NMAX 16005

using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");

vector <int> a[NMAX];
bool viz[NMAX];
int v[NMAX], n, i, maxx = INT_MIN, x, y;

void dfs(int nod)
{
    viz[nod] = 1;
    for(vector <int> :: iterator it = a[nod].begin(); it != a[nod].end(); ++ it)
        if(!viz[*it])
        {
            dfs(*it);
            if(v[*it] > 0)
                v[nod] += v[*it];
        }
}

int main()
{
    f >> n;
    for(i = 1; i <= n; ++ i)
        f >> v[i];

    while(f >> x >> y)
    {
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    for(i = 1; i <= n; ++ i)
        maxx = max(maxx, v[i]);
    g << maxx << "\n";
    return 0;
}