#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
vector<int> a[16001];
int f[16001];
int val[16001];
int sol[16001];
int i,n,Max=-2000000,x,y;

void dfs (int nod) {
    f[nod]=1;
    sol[nod]=val[nod];
    for (int i=0;i<a[nod].size();i++) {
        int vecin=a[nod][i];
        if (f[vecin]==0) {
            dfs(vecin);
            if (sol[vecin]>0) sol[nod]+=sol[vecin];
        }
    }
    Max=max(Max,sol[nod]);
}

int main() {
    ifstream fin("asmax.in");
    ofstream fout("asmax.out");
    fin>>n;
    for (i=1;i<=n;i++) {
        fin>>val[i];
    }
    for (i=1;i<=n-1;i++) {
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    fout<<Max;
    return 0;
}