#include <fstream>
#include <vector>

using namespace std;

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

int n, mini, s[16005], fr[16005], a[16005], maxi;
vector<int> v[16005];

void dfs(int nod)
{
    s[nod] = a[nod]; fr[nod] = 1;
    for(auto x : v[nod])
        if(!fr[x])
        {
            dfs(x);
            if(s[x] > 0)
                s[nod] += s[x];
        }

    maxi = max(maxi, s[nod]);
}

int main()
{
    f >> n;
    for(int i = 1; i <= n; i ++)
        f >> a[i];

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

    maxi = -100000;
    dfs(1);

    g << maxi;
    return 0;
}