#include <bits/stdc++.h>
#define FILE_NAME "asmax"
#define fast ios_base :: sync_with_stdio(0); cin.tie(0);
#pragma GCC optimize("O3")
#define NMAX 16010
using namespace std;

ifstream f(FILE_NAME ".in");
ofstream g(FILE_NAME ".out");

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pi;
typedef pair<ld,ld> pct;

const ll inf = 1LL << 60;
const ll mod = 1e9 + 7;
const ld eps = 1e-9;


void add(ll &a , ll b)
{
    a += b;
    a %= mod;
}

void sub(ll &a, ll b)
{
    a = (a - b + mod) % mod;
}

int n, d[NMAX];
bitset <NMAX> viz, start[NMAX];
vector <int> G[NMAX];

void DFS(int nod)
{
    viz[nod] = 1;
    for(auto it : G[nod])
        if(!viz[it])
        {
            DFS(it);
            d[nod] = max(d[nod], d[nod] + d[it]);
        }
}
int main()
{
    f >> n;
    for(int i = 1; i <= n; ++i)
        f >> d[i];
    for(int x,y, i = 1; i < n; ++i)
    {
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1);
    int ans = - (1 << 30);
    for(int i = 1; i <= n; ++i)
        ans = max(ans, d[i]);
    g << ans;
    f.close();
    g.close();
    return 0;
}