#include <stdio.h>
#include <list>
#include <climits>

/* Nume fisiere intrare/iesire */
#define FIN  "asmax.in"
#define FOUT "asmax.out"

/* Numar maxim de intrari */
#define NMAX 16001

/* fisiere */
FILE *in, *out;

/* numarul de noduri */
int N;

/* arbore reprezentat prin liste de adiacenta */
std::list<int> graph[NMAX];

/* suma maxima */
long smax = LONG_MIN / 2;

/* valorile din noduri */
long values[NMAX];

/* vector de dinamica */
long dinamica[NMAX];

bool visited[NMAX];

int DFS(int node){
    long sum = 0;
    visited[node] = true;
    sum += values[node];

    for(std::list<int>::iterator it = graph[node].begin(); it != graph[node].end(); ++it){
        int p = *it;
        if ( !visited[p] ) {
            sum += DFS(p);
        }
    }
    if (sum > smax) smax = sum;

    if (sum > 0) return sum;

    return 0;
}

void solve(){
    DFS(1);
}

int main(){
    /* deschidere fisiere */
    in = fopen(FIN, "rt");
    out = fopen(FOUT, "wt");
    if(!in || !out) return 1;

    fscanf(in, "%d", &N);
    for(int i=1; i <= N; i++) fscanf(in, "%li", &values[i]);

    for(int i=1; i < N; i++){
        int a,b;
        fscanf(in, "%d%d", &a, &b);

        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    solve();

    fprintf(out, "%li", smax);

    /* inchidere fisiere */
    fclose(in);
    fclose(out);
    return 0;
}