#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
#define MAXN 16010
ifstream f("asmax.in");
ofstream g("asmax.out");
vector <int> G[MAXN];
int maxim,v[MAXN],viz[MAXN],n,x,y;
void dfs(int nod){
    viz[nod]=1;
    for(auto it:G[nod]){
        if(!viz[it]){
            dfs(it);
        if(v[it]>0){
            v[nod]+=v[it];
            }
        }
    }
}
int main()
{
    f>>n;
    for(int i=1;i<=n;i++)
        f>>v[i];
    for(int i=1;i<n;i++){
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    maxim=v[1];
    for(int i=2;i<=n;i++){
        maxim=max(maxim,v[i]);
    }
    g<<maxim;
    return 0;
}