#include <algorithm>
#include <fstream>
#include <vector>

using namespace std;

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

const int mare = 20000000;
vector <int> ls[16005];
int a[16005], x, y, n, smin = mare, smax, i, nmin;
bool pos[16000005];
bool viz[16005];

void df(int k){
    int i, l = ls[k].size();
    viz[k] = 1;
    /*for (i = smax; i >= smin; i--)
        if (pos[i] == 1)
            pos[i+x] = 1;*/
    if (smin + x < smin)
        smin = smin + x;
    if (smax + x > smax)
        smax = smax + x;

    for (i = 0; i < l; i++){
        if (viz[ls[k][i]] == 0)
            df(ls[k][i]);
    }
}

int main(){
    f >> n;
    for (i = 1; i <= n; i++)
        f >> a[i];
    for (i = 1; i <= n-1; i++){
        f >> x >> y;
        ls[x].push_back(y);
        ls[y].push_back(x);
        nmin = min(nmin, x);
        nmin = min(nmin, y);
    }
    df(nmin);
    g << smax;
    /*for (i = smax; pos[i] == 0; i--);
    g << i;*/
    return 0;
}