#include <fstream>
#include <vector>
#include <climits>
using namespace std;
const int nmax = 16005;
int n;
vector<int> l[nmax];
int dp[nmax], val[nmax];
void dfs(int node, int father){
    dp[node] += val[node];
    for(auto son: l[node]){
        if(son != father){
            dfs(son, node);
            if(dp[son] > 0){
                dp[node] += dp[son];
            }
        }
    }
}
int main(){
    ifstream f("asmax.in");
    ofstream g("asmax.out");
    f >> n;
    for(int i = 1; i <= n; i++){
        f >> val[i];
    }
    for(int i = 1; i <= n - 1; i++){
        int x, y;
        f >> x >> y;
        l[x].push_back(y);
        l[y].push_back(x);
    }
    dfs(1, 0);
    int maxim = INT_MIN;
    for(int i = 1; i <= n; i++){
        maxim = max(maxim, dp[i]);
    }
    g << maxim << '\n';   
}