#include <bits/stdc++.h>
#define Nmax 16003
#define pb(x) push_back(x)
#define Max(x, y) x > y ? x : y
FILE *fin  = freopen("asmax.in", "r", stdin);
FILE *fout = freopen("asmax.out", "w", stdout);

using namespace std;
int n, dp[Nmax], sol;
vector <int> G[Nmax];
bitset <Nmax> vis;
void read()
{
    int i, x, y;
    scanf("%d", &n);
    for(i = 1; i <= n; ++ i)
        scanf("%d", &dp[i]);

    for(i = 1; i < n; ++ i)
    {
        scanf("%d %d", &x, &y);
        G[x].pb(y);
        G[y].pb(x);
    }
}
void DFS(int x)
{
    vis.set(x);
    for(int i = 0; i < G[x].size(); ++ i)
    {
        int y = G[x][i];
        if(vis.test(y) == 0)
        {
            DFS(y);
            if(dp[y] > 0)
                dp[x] += dp[y];
        }
    }
    sol = Max(sol, dp[x]);
}
void write()
{
    printf("%d\n", sol);
}
int main()
{
    read();
    DFS(1);
    write();
    return 0;
}