//#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
using namespace std;
queue <int> q;
vector<int> v[16005];
int d1[16005],d2[16005],cost[16005],tata[16005],f[16005],maxim=-1;
int main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    int n,a,b;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>cost[i];
    }
    for(int i=1;i<n;i++){
        cin>>a>>b;
        v[a].push_back(b);
        tata[b]=a;
        f[a]++;
    }
    for(int i=1;i<=n;i++){
        if(f[i]==0)
            q.push(i);
    }
    int x;
    while(q.empty()==false){
        x=q.front();
        q.pop();
        int sum=0;
        maxim=-1;
        for(int i=0;i<v[x].size();i++){
            sum+=d1[v[x][i]];
            if(maxim<d2[v[x][i]])
                maxim=d2[v[x][i]];
        }
        sum+=cost[x];
        if(sum<0){
            sum=0;
        }
        d1[x]=sum;
        d2[x]=max(maxim,sum);
        ///verific ca sa nu scad tatal radacinei
        if(tata[x]<=n and tata[x]>=1){
            f[tata[x]]--;
            if(f[tata[x]]==0)
                q.push(tata[x]);
        }
    }
    cout<<d2[x];
    return 0;
}