#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
#define nmax 16005
ifstream f("asmax.in");
ofstream g("asmax.out");

int cost[nmax],dp[nmax],n;
bool viz[nmax];
vector<int>Q[nmax];

void dfs(int nod)
{
    dp[nod]=cost[nod];
    viz[nod]=true;
    for (auto w:Q[nod])
    {
        if (!viz[w])
        {
            dfs(w);
            if (dp[w]>0)
                dp[nod]+=dp[w];
        }
    }
}

void read()
{
    f>>n;
    for (int i=1;i<=n;++i)
        f>>cost[i];
    for(int i=1;i<n;++i)
    {
        int a,b;
        f>>a>>b;
        Q[a].push_back(b);
        Q[b].push_back(a);
    }
}

int main()
{
    read();
    dfs(1);
    int mx=-1;
    for (int i=1;i<=n;++i)
        mx=max(dp[i],mx);
    g<<mx;
    return 0;
}