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

using namespace std;
int n,i,x,y;
int maxi;
int d[16001],v[16001];
bool viz[16001];

vector<int>g[16001];

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

void dfs(int x)
{
    viz[x]=true;
    d[x]=v[x];
    for (auto y: g[x])
    {
        if (viz[y]==false)
        {
            dfs(y);
            if (d[y]>=0) d[x]+=d[y];
        }
    }
}

int main()
{
    cin>>n;
    for (i=1;i<=n;i++) cin>>v[i];
    for (i=2;i<=n;i++)
    {
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    maxi=d[1];
    for (i=1;i<=n;i++)
    {
        maxi=max(maxi,d[i]);
    }
    cout<<maxi;
}