#include <fstream>
#include <vector>

using namespace std;

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

int val[16001],scor[16001],maxx;
vector<int> a[16001];
bool f[16001];

void dfs(int x)
{
    f[x] = true;
    scor[x] = val[x];
    for (auto y: a[x])
    {
        if (!f[y])///y este fiu al lui x in arborele DFS
        {
            dfs(y);
            if (scor[y] > 0)
            {
                scor[x] += scor[y];
            }
        }
    }
}

int main()
{
    int n;
    fin>>n;
    for(int i=1;i<=n;i++)
        fin>>val[i];
    for(int i=1;i<n;i++)
    {
        int x,y;
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    maxx=scor[1];
    for(int i=2;i<=n;i++)
        maxx=max(maxx,scor[i]);
    fout<<maxx;
    return 0;
}