#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
const int NMAX=16001;
vector<int> G[NMAX];
int n,v[NMAX],s[NMAX];
void DFS(int nod,int tata)
{
    for(int i=0;i<G[nod].size();i++)
        if(G[nod][i]!=tata)
    {
        DFS(G[nod][i],nod);
        if(s[G[nod][i]]>0)
            s[nod]+=s[G[nod][i]];
    }
}
int main()
{
    int x,y;
    f>>n;
    for(int i=1;i<=n;i++)
        f>>v[i],s[i]=v[i];
    for(int i=1;i<n;i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1,0);
    int maxim=-999999999;
    for(int i=1;i<=n;i++)
        maxim=max(maxim,s[i]);
    g<<maxim;
    return 0;
}