#include<stdio.h>
#include<algorithm>
#include<vector>
using namespace std;

const int NMAX = 16005;

vector <int> graph[NMAX];
int res, vis[NMAX], sum[NMAX], val[NMAX];

void dfs (int node) {
    vector <int>::iterator it;

    vis[node] = 1;
    sum[node] = val[node];
    for(it = graph[node].begin(); it != graph[node].end(); ++ it)
        if(!vis[*it]) {
            dfs(*it);
            if(sum[*it] > 0)
                sum[node] += sum[*it];
        }

    res = max(res, sum[node]);
}

int main() {
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);
    int n, m, i, x, y;

    scanf("%d", &n);
    for(i = 1; i <= n; ++ i)
        scanf("%d", &val[i]);
    for(i = 1; i < n; ++ i) {
        scanf("%d%d", &x, &y);
        graph[x].push_back(y);
        graph[y].push_back(x);
    }

    dfs(1);

    printf("%d\n", res);
    return 0;
}