#include <fstream>
#include <vector>

using namespace std;

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

const int N = 16001;
vector <int> a[N];
bool viz[N];
int s[N], n, maxi = -1001;

void dfs(int nod)
{
    viz[nod] = true;

    for(unsigned int i=0; i < a[nod].size(); i++)
    {
        if(!viz[a[nod][i]])
        {
            dfs(a[nod][i]);

            if(s[a[nod][i]] > 0)
            {
                s[nod] += s[a[nod][i]];
            }
        }
    }
}

int main()
{
    in >> n;

    for(int i=1; i<=n; i++)
    {
        in >> s[i];
    }

    for(int i=1; i<n; i++)
    {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    dfs(1);

    for(int i=1; i<=n; i++)
    {
        if(s[i] > maxi)
        {
            maxi = s[i];
        }
    }

    out << maxi;

    return 0;
}