#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], v[Nmax];
bool viz[Nmax], fr[Nmax];

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

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

int main()
{
    Read();
    Solve();
    return 0;
}