#include<fstream>
#include<vector>
using namespace std;
ofstream fout("asmax.out");
ifstream fin("asmax.in");

constexpr int NMAX = 16005;

int n, x, y;
int valori[NMAX], viz[NMAX], sol[NMAX], Max = -1005;
vector<int> Graf[NMAX];

void DFS(int nod)
{
    sol[nod] = valori[nod];
    viz[nod] = 1;
    for(const auto & nouNod : Graf[nod])
        if(viz[nouNod] != 1) {
            DFS(nouNod);
            if(sol[nouNod] >= 0)
                sol[nod] += sol[nouNod];
        }

    Max = max(Max, sol[nod]);
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++)
        fin >> valori[i];
    while(fin >> x >> y) {
        Graf[x].push_back(y);
        Graf[y].push_back(x);
    }

    DFS(1);
    fout << Max << '\n';
    return 0;
}