#include <iostream>
#include <fstream>

using namespace std;

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

int n,v[16001],st[16001],dr[16001],suma,summax;

void sum(int nod){
    suma+=v[nod];
    if(suma>summax)
        summax=suma;
    for(int i=1;i<n;i++){
        if(st[i]==nod)
            sum(dr[i]);
    }
}

int main()
{
    int a,b;
    in>>n;
    for(int i=1;i<=n;i++)
        in>>v[i];
    for(int i=1;i<n;i++)
        in>>st[i]>>dr[i];
    for(int i=1;i<=n;i++){
        suma=0;
        sum(i);
    }
    out<<summax;
    return 0;
}