#include <iostream>
#include <vector>
#include <fstream>
using namespace std;

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

const int INF=1e9;

void dfs(int x, vector<vector<int>> &a, vector<bool> &viz, vector<int> &val)
{
    viz[x]=true;
    for(auto y:a[x])
    {
        if(!viz[y])
        {
            dfs(y,a,viz,val);
            if(val[y]>0)
            {
                val[x]+=val[y];
            }
        }
    }
}

int main()
{
    int n;
    in>>n;
    vector<vector<int>> a(n+1);
    vector<bool> viz(n+1,false);
    vector<int> val(n+1, -INF);
    for(int i=1;i<=n;i++)
    {
        in>>val[i];
    }
    for(int i=1;i<=n-1;i++)
    {
        int x,y;
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1,a,viz,val);
    in.close();
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            dfs(i,a,viz,val);
        }
    }
    int val_max=-INF;
    for(int i=1;i<=n;i++)
    {
        val_max=max(val_max,val[i]);
    }
    out<<val_max<<"\n";
    return 0;
}