#include <bits/stdc++.h>
#define N 16010
using namespace std;

int bestsum = -(2e9),n,a,b;
int val[N];
bool viz[N];
vector <int> v[N];

int dfs(int x)
{
    int sum = val[x];
    viz[x]=1;
    for(int i=0;i<v[x].size();i++)
    {
        if(!viz[v[x][i]])
        {
            int sum2 = dfs(v[x][i]);
            if(sum2>0) sum+=sum2;
        }
    }
bestsum=max(sum, bestsum);
        return sum;
}

int main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>val[i];
    for(int i=1;i<n;i++)
    {
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1);
    cout<<bestsum;

    return 0;
}