#include <bits/stdc++.h>
#define Nmax 16003
#define INF 2000000000

using namespace std;

int n;
int v[Nmax],dp[Nmax],sol;
vector<int>L[Nmax];
bitset<Nmax>viz;

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

void DFS(int x)
{
    viz[x]=1;
    dp[x]=v[x];
    for(auto y : L[x])
    {
        if(viz[y]==0)
        {
            DFS(y);
            if(dp[y]>0)
                dp[x]+=dp[y];
        }
    }
}

int main()
{
    Citire();
    DFS(1);
    sol=-INF;
    int i;
    for(i=1;i<=n;++i)
        sol=max(sol,dp[i]);
    ofstream fout("asmax.out");
    fout<<sol<<"\n";
    fout.close();
    return 0;
}