#include <fstream>
#include <vector>
#define DIM 16001
#define INF 16000001
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n,x,y,sol,v[DIM],d[DIM];
bool viz[DIM];
vector<int> l[DIM];

void dfs(int nod) {
    viz[nod]=1;
    d[nod]=v[nod];
    for (int i=0;i<l[nod].size();i++) {
        int vec=l[nod][i];
        if (viz[vec]==0) {
            dfs(vec);
            if (d[vec]>0)
                d[nod]+=d[vec];
        }
    }
    sol=max(sol,d[nod]);
}

int main() {
    fin>>n;
    sol=-INF;
    for (int i=1;i<=n;i++) {
        fin>>v[i];
        sol=max(sol,v[i]);
    }
    for (int i=1;i<n;i++) {
        fin>>x>>y;
        l[x].push_back(y);
        l[y].push_back(x);
    }
    dfs(1);
    fout<<sol;
    return 0;
}