#include <iostream>
#include <fstream>
#include <vector>

using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int N=16001;
vector<int> a[N];

int n,d[N],sum[N];
bool v[N];

void citire()
{
    int x,y;
    in>>n;
    for(int i=1;i<=n;i++)
        in>>d[i];
    for(int i=1;i<n;i++)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}
void dfs(int x)
{
    sum[x]=d[x];
    v[x]=true;
    for(size_t i=0;i<a[x].size();i++)
        if(!v[a[x][i]])
        {
            dfs(a[x][i]);
            if(sum[a[x][i]]>0)
                sum[x]+=sum[a[x][i]];
        }
}
int main()
{
    int max=-10000001;
    citire();
    dfs(1);
    for(int i=1;i<=n;i++)
        if(sum[i]>max)
            max=sum[i];
    out<<max;
    return 0;
}