#include <bits/stdc++.h>
using namespace std;
const int MAXN =  16 * 1e3 + 2;
int s[MAXN];
bool vizitat[MAXN];
vector <int> g[MAXN];
void dfs(int node){
    vizitat[node] = true;
    for(auto y : g[node]){
        if(!vizitat[y]){
            dfs(y);
            s[node] = s[node] + max(s[y], 0);
        }
    }
}
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int main(){
    int n, indice;
    fin >> n;
    for(int i = 1; i <= n; ++i){
        int x;
        fin >> x;
        s[i] = x;
    }
    for(int i = 1; i < n; ++i){
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    int maxim = -1e8;
    for(int i = 1; i <= n; ++i){
        maxim = max(maxim, s[i]);
    }
    fout << maxim;
    return 0;
}