#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
const int N=16001;
vector <int> v[N];
long long s[N],a[N];
int n;
bool viz[N];
void citire()
{
    f>>n;
    for(int i=1;i<=n;i++){
        f>>a[i];
    }
    for(int i=1;i<n;i++){
        int x,y;
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    f.close();
}
void dfs(int x)
{
    viz[x]=true;
    int y;
    for(int i=0;i<v[x].size();i++){
        y=v[x][i];
        if(!viz[y]){
            dfs(y);
            if(a[y]>0)
                a[x]+=a[y];
                }
    }
}
int main()
{
    citire();
    long long r=-16000001;
    dfs(1);
    for(int i=1;i<=n;i++)
        r=max(r,a[i]);
    g<<r;
    return 0;
}