#include <fstream>
#include <vector>

using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");

const int nmax = 16000;
long long graf[nmax + 1];
int viz[nmax + 1];
vector<int>g[nmax + 1];

void dfs(int node)
{
    viz[node] = 1;
    for(int i = 0; i < g[node].size(); i++)
    {
        int vecin = g[node][i];
        if(viz[vecin] == 0)
        {
            dfs(vecin);
            if(graf[vecin] > 0)
                graf[node] += graf[vecin];
        }
    }
}
int main()
{
    int n;
    in>>n;
    for(int i = 1; i <= n; i++)
        in>>graf[i];
    for(int i = 1; i <= n-1; i++)
    {
        int x,y;
        in>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    long  long maxi = -1e9;
    for(int i = 1;i <= n; i++)
        maxi = max(graf[i],maxi);
    out<<maxi;
    return 0;
}