#include <iostream>
#include <fstream>
#include <vector>
#define pb push_back

using namespace std;

const int NMAX=16005;
vector <int> G[NMAX];

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

int n, v[NMAX], dp[NMAX], mx;
bool viz[NMAX];

void dfs(int node)
{
    viz[node]=1;
    dp[node]=v[node];
    for(int i=0;i<G[node].size();i++)
    {
        if(!viz[G[node][i]])
        {
            dfs(G[node][i]);
            dp[node]=max(dp[node],dp[node]+dp[G[node][i]]);
        }
    }
    if(dp[node]>mx)
        mx=dp[node];
}

int main()
{
    fin>>n;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
    }
    for(int i=1;i<n;i++)
    {
        int x, y;
        fin>>x>>y;
        G[x].pb(y);
        G[y].pb(x);
    }
    dfs(1);
    fout<<mx;
    return 0;
}