#include <fstream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <set>
#include <stack>
#include <iomanip>
#include <cstring>

#define NMax 16005
#define INF 0x3f3f3f3f
using namespace std;

int viz[NMax],s[NMax],a[NMax];
vector<int> G[NMax];
queue<int> q;
int n,x,y;

void bfs(int k){
    q.push(k);
    viz[k] = 1;
    while(!q.empty()){
        int nod = q.front();
        q.pop();
        for(int i = 0; i < G[nod].size(); ++i){
            if(!viz[G[nod][i]]){
                viz[G[nod][i]] = viz[nod] + 1;
                q.push(G[nod][i]);
            }
        }
    }
}
int main()
{
    ifstream f("asmax.in");
    ofstream g("asmax.out");
    f >> n;
    for(int i = 1; i <= n; ++i)
        f >> a[i];
    for(int i = 1; i < n; ++i){
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    bfs(1);
    for(int i = 1; i <= n; ++i){

        q.push(i);
        s[i] += a[i];
        while(!q.empty()){
            int nod = q.front();
            q.pop();
            for(int j = 0; j < G[nod].size(); ++j){
                if(viz[G[nod][j]] > viz[nod]){
                    s[i] += a[G[nod][j]];
                    q.push(G[nod][j]);
                }
            }
        }
    }
    int mx = -INF;
    for(int i = 1; i <= n; ++i){

        for(int j = 1; j <= n; ++j){
            if(i != j)
                mx = max(mx, s[i] - s[j]);
        }
    }
    g << mx;
    return 0;
}