#include <fstream>
#include <vector>
#include <algorithm>

#define MAX 16384
#define INF 0x3f3f3f3f

using namespace std;

vector<int> v[MAX];
int val[MAX], n, a, b, maxim = -INF, dp[MAX];
bool visited[MAX];

int dfs(int nod)
{
    visited[nod] = true;
    dp[nod] = val[nod];
    for(int i = 0; i < v[nod].size(); i++)
    {
        if(!visited[v[nod][i]])
        {
            int k = dfs(v[nod][i]);
            if(k > 0)
                dp[nod] += k;
        }
    }
    maxim = max(maxim, dp[nod]);
    return dp[nod];

}

int main()
{
    ifstream in("asmax.in"); in>>n;
    for(int i = 1; i <= n; i++) in>>val[i];
    for(int i = 1; i < n; i++)
    {
        in>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    } in.close();
    dfs(1);
    ofstream out("asmax.out"); out<<maxim; out.close();
    return 0;
}