#include<fstream>
#include<iostream>
#include<vector>
using namespace std;

const int nmax = 16000;
int n, m, val[nmax+1],maxsum[nmax+1];
bool viz[nmax+1];
vector<int>a[nmax+1];


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



void smax(int nod)
{
    viz[nod] = 1;
    int s;
    maxsum[nod] = val[nod];
        for(int vecin : a[nod])
        if(viz[vecin] == 0)
        {
            smax(vecin);
            s = maxsum[vecin];
            if(s > 0)maxsum[nod] += s;
        }
}

int main()
{
    fin>>n;

    for(int i = 1; i <= n; i++)
    {
        int x;
        fin>>x;
        val[i] = x;
    }
    int x,y;
    while(fin>>x>>y)
    {

        a[x].push_back(y);
        a[y].push_back(x);

    }
    smax(1);

    int maxim = maxsum[1];
    for(int i = 2; i <=n; i++)
        if(maxsum[i] > maxim)
            maxim = maxsum[i];

            fout<<maxim;
        }