#include <bits/stdc++.h>

using namespace std;

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

int n;
vector<vector<int>>a;
vector<int>dp;
vector<int> viz,v;

void dfs(int nod,int gr){
    viz[nod]=gr;
    ///cout<<ndo<<endl;
    for(auto f:a[nod]){
        if(!viz[f]) dfs(f,gr+1);
    }
    dp[nod]=v[nod];
    for(auto f:a[nod]){
        if(viz[f]==gr+1){
            if(dp[f]>0){
                dp[nod]+=dp[f];
            }
        }
    }
}

int main(){
    fin>>n;
    a.resize(n+1);
    viz.resize(n+1);
    v.resize(n+1);
    dp.resize(n+1);
    for(int i=1;i<=n;i++) fin>>v[i];
    int x,y;
    for(int i=0;i<n-1;i++){
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1,0);
    int rez=-999999999;
    for(int i=1;i<=n;i++){
       rez=max(rez,dp[i]);
    }
    fout<<rez;
    return 0;
}