#include <bits/stdc++.h>
using namespace std;

#define all(v) (v).begin(),(v).end()
#define pb emplace_back
#define rep(i, n) for(int i=0;i<(n);i++)
#define foa(e, v) for(auto& e : v)
#define dout(a) cout<<fixed<<setprecision(10)<<a<<'\n';
#define Cout(a) cout<<a<<'\n';

using ll = long long;
using ld = long double;
using Int = __int128;
template <class T> using pqr = priority_queue<T, vector<T>, greater<T>>;

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
    bool compare = a < b;
    if(compare) a = b;
    return compare;
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
    bool compare = a > b;
    if(compare) a = b;
    return compare;
}
template <typename T> inline T back(std::set<T> &s) {
    return *s.rbegin();
}
template <typename T> inline T back(std::multiset<T> &s) {
    return *s.rbegin();
}
template <typename T> inline T pop_back(std::set<T> &s) {
    auto it = prev(s.end());
    T val = *it;
    s.erase(it); 
    return val;
}
template <typename T> inline T pop_back(std::multiset<T> &s) {
    auto it = prev(s.end());
    T val = *it;
    s.erase(it); 
    return val;
}

const int dy[8] = {-1, 0, 0, 1, 1, -1, 1, -1};
const int dx[8] = {0, -1, 1, 0, -1, -1, 1, 1};

const ll MOD7 = 1000000007, MOD998 = 998244353, INF = (3LL << 59);
const int inf = 1 << 30;
const char br = '\n';

void solve() {
    ll n; cin >> n;
    vector<ll> s(n);
    rep(i, n) cin >> s[i];
    vector<vector<int>> v(n);
    rep(i, n - 1) {
        int a, b; cin >> a >> b;
        a --;b --;
        v[a].pb(b);
        v[b].pb(a);
    }
    vector<ll> dp(n, 0);
    vector<int> ord(n);
    iota(all(ord), 0);
    sort(all(ord), [&](int i, int j) {
        return s[i] > s[j];
    });
    foa(i, ord) {
        ll m = s[i];
        foa(e, v[i]) if(s[e] > s[i]) {
            chmax(m, s[i] + dp[e]);
        }
        dp[i] = m;
    }
    cout << *max_element(all(dp)) << endl;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int testcase = 1; 
    // cin >> testcase;
    while(testcase --) solve();

    return 0;
}