#include <bits/stdc++.h>
#define NMAX 16001
#define INF 1<<30

using namespace std;

ifstream fin("asmax.in");
ofstream fout("asmax.out");

vector<int> G[NMAX];
int C[NMAX], V[NMAX];
int n, a, b, c;
bool use[NMAX];

void DFS(int node) {
    use[node] = 1;
    V[node] = C[node];
    for(int i = 0; i < G[node].size(); i++) {
        if(!use[G[node][i]]) {
            DFS(G[node][i]);
            if(V[G[node][i]] > 0) V[node] += V[G[node][i]];
        }
    }
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++) {
        fin >> C[i];
    }
    for(int i = 1; i < n; i++) {
        fin >> a >> b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    DFS(1);
    int sol = -INF;
    for(int i = 1; i <= n; i++) {
        if(V[i] > sol) sol = V[i];
    }
    fout << sol << '\n';
    return 0;
}