#include <fstream>
#include <vector>
#include <cstring>
#define DIM 16010
using namespace std;
ifstream fin ("asmax.in");
ofstream fout("asmax.out");
int n, x, y, maxim, j, i;
int viz[DIM], S[DIM], val[DIM];
vector <int> g[DIM];

void dfs(int nod) {
    viz[nod] = 1;
    for (int i=0;i<g[nod].size(); i++) {
        int vecin = g[nod][i];
        if (viz[vecin] == 0) {
            dfs(vecin);
            if (val[vecin]>0)
                val[nod] += val[vecin];
        }
    }
    maxim=max(maxim, val[nod]);
}

int main () {
    fin>>n;
    for (i=1;i<=n;i++) {
        fin>>val[i];
    }
    for (i=1;i<n;i++) {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    fout<<maxim;
    return 0;
}