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

using namespace std;

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

int n;
vector <int> L[Nmax];
int dp[Nmax]; ///dp[i]=suma maxima obtinuta in subarborele i
int v[Nmax];
bool viz[Nmax], fr[Nmax];///fr[i]=true daca i are grad intern 0

void Dfs(int nod)
{
    viz[nod] = true;
    dp[nod] = v[nod];
    for(auto i : L[nod])
        if(!viz[i])
        {
            Dfs(i);
            if(dp[i] > 0)
                dp[nod] += dp[i];
        }
}

void Citire()
{
    int i, x, y;
    fin >> n;
    for(i = 1; i <= n; i++)
        fin >> v[i];
    for(i = 1; i <= n; i++)
    {
        fin >> x >> y;
        fr[y] = true;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    fin.close();
}

void Rezolvare()
{
    int i, M;
    for(i = 1; i <= n; i++)
        if(!fr[i])
            Dfs(i);
    M = dp[1];
    for(i = 2; i <= n; i++)
        M = max(M, dp[i]);
    fout << M << "\n";
    fout.close();
}

int main()
{
    Citire();
    Rezolvare();
    return 0;
}