#include <fstream>
#include <vector>
#include <climits>

using namespace std;

void dfs(vector<vector<int>> &graph, vector<int> &asmax, vector<int> v,
         int node, int father){
    asmax[node] = v[node];
    for(int son : graph[node]){
        if(son != father){
            dfs(graph, asmax, v, son, node);
            if(v[son] >= 0){
                asmax[node] += v[son];
            }
        }
    }
}

int main(){
    int n;
    ifstream fin("asmax.in");
    ofstream fout("asmax.out");
    fin >> n;
    vector<int> v, asmax(n+1);
    vector<vector<int>> graph(n+1, vector<int>());
    v.push_back(0);
    for(int i = 1; i <= n; i++){
        int x;
        fin >> x;
        v.push_back(x);
    }
    for(int i = 1; i <= n-1; i++){
        int x, y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    dfs(graph, asmax, v, 1, 0);
    int sol = INT_MIN;
    for(int i = 1; i <= n; i ++){
        sol = max(sol, asmax[i]);
    }
    fout << sol;
    return 0;
}