#include<fstream>
#include<vector>
using namespace std;
int n, i, x, y, maxim;
int viz[16002], w[16002], d[16002];
vector<int> v[16002];
ifstream fin("asmax.in");
ofstream fout("asmax.out");
void dfs(int x){
    viz[x] = 1;
    d[x] = w[x];
    for(int i = 0; i < v[x].size(); i++){
        int vecin = v[x][i];
        if(viz[vecin] == 0){
            dfs(vecin);
            if(d[vecin] > 0){
                d[x] += d[vecin];
            }
        }
    }
}
int main(){
    fin>> n;
    for(i = 1; i <= n; i++){
        fin>> w[i];
    }
    for(i = 1; i < n; i++){
        fin>> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    maxim = -1000000000;
    for(i = 1; i <= n; i++){
        maxim = max(maxim, d[i]);
    }
    fout<< maxim <<"\n";
    return 0;
}