#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream fin ("asmax.in");
ofstream fout ("asmax.out");

struct qq
{
    int n;
    vector<int> i;
};

vector<qq> g;

int n, smax = -0x3f3f3f3f, maxi = -0x3f3f3f3f;
bool v[16001];

int dfs(int na)
{
    v[na] = true;

    for (int x : g[na].i)
        if (v[x] == false)
            g[na].n += dfs(x);

    if (g[na].n > 0) return g[na].n;
    return 0;
}

int main()
{
    fin >> n;
    g = vector<qq>(n + 1);

    for (int i = 1; i <= n; ++ i)
        {
            fin >> g[i].n;
            maxi = max(maxi, g[i].n);
        }
    int x, y;
    while(fin >> x >> y)
    {
        g[x].i.push_back(y);
        g[y].i.push_back(x);
    }

    for (int i = 1; i <= n; ++ i)
        if (g[i].n > 0)
            smax = max(smax, dfs(i));
    fout << max(smax, maxi);

    return 0;
}