#include <fstream>
#include <vector>

using namespace std;

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

int n, x, y, v[16005];
int visit[16005], dp[16005], maxm;
vector <int> g[16005];

void dfs(int i){
    visit[i] = 1;
    dp[i] = v[i];
    for(int j=0; j<g[i].size(); j++)
        if(visit[g[i][j]] == 0){
            dfs(g[i][j]);
             if(dp[g[i][j]] > 0)
                    dp[i] += dp[g[i][j]];
        }
}


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