#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
vector <int> graf[16005];
int v[16005];
int scor[16005];
bool visited[16005];
void dfs(int x)
{
    int y;
    visited[x]=1;
    for(unsigned int i=0; i<graf[x].size(); i++)
    {
        y=graf[x][i];
        if(visited[y]==0)
        {
            dfs(y);
            if(scor[y]>0)
                scor[x]+=scor[y];
        }

    }
    scor[x]+=v[x];
}
int main()
{
    int n,x,y;
    in>>n;
    for(int i=1; i<=n; i++)
        in>>v[i];
    for(int i=1; i<=n-1; i++)
    {
        in>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    dfs(1);
    int maxim=scor[1];
    for(int i=2; i<=n; i++)
        maxim=max(scor[i],maxim);
    out<<maxim;
    return 0;
}