#include <iostream>
#include <fstream>
#include <vector>
#define nm 16010
using namespace std;

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


int n,m;
vector <int> G[nm];
int v[nm],viz[nm],rez, x, y;

void dfs(int nod)
{
    viz[nod] = 1;
     for(int i=0;i<G[nod].size();i++)
     {
         if(!viz[G[nod][i]])
         {
             dfs(G[nod][i]);
             if(v[G[nod][i]] > 0)
                v[nod]+=v[G[nod][i]];
         }
     }
}

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

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

    dfs(1);
    rez = v[1];

    for(int i=1;i<=n;i++)
    {
        rez=max(rez,v[i]);
    }
    fout<<rez;
    return 0;
}