#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;
const int NMAX = 16005;
const int INF = 2000000000;

int cost[NMAX], val;
vector <int> g[NMAX];
bool viz[NMAX];

int DFS(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < g[nod].size(); ++i)
        if(!viz[g[nod][i]])
        {
            val = DFS (g[nod][i]);
            if(val > 0)
                cost[nod] += val;
        }
    return cost[nod];
}
int main()
{
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);
    int a, b, n, ans;
    scanf("%d", &n);
    for(int i = 1; i <= n; ++i)
        scanf("%d", &cost[i]);
    for(int i = 1; i < n; ++i)
    {
        scanf("%d%d", &a, &b);
        g[a].push_back(b);
        g[b].push_back(a);
    }
    DFS(1); ans = -INF;
    for(int i = 1; i <= n; ++i)
        ans = max(ans, cost[i]);
    printf("%d\n", ans);
    return 0;
}