#include <bits/stdc++.h>
#define DIM 16010
#define INF 1000000000
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
vector <int> L[DIM];
int f[DIM],val[DIM],d[DIM];
int n,i,a,b,sol=-INF;
void dfs(int nod){
    f[nod]=1;
    for(int i=0;i<L[nod].size();i++){
        int vecin=L[nod][i];
        if(!f[vecin]){
            dfs(vecin);
            if(d[vecin]>0)
                d[nod]+=d[vecin];

        }
    }
    sol=max(sol,d[nod]);
}
int main(){
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>d[i];
    for(i=1;i<n;i++){
        fin>>a>>b;
        L[a].push_back(b);
        L[b].push_back(a);
    }
    dfs(1);
    fout<<sol;
    return 0;
}