#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(n);i++)

int main(){
    int n;
    cin >> n;
    vector<ll> s(n);
    rep(i,n) cin >> s[i];

    vector<vector<int>> e(n);
    rep(i,n-1){
        int a, b;
        cin >> a >> b;
        a--; b--;
        if(s[a]<s[b]) e[b].push_back(a);
        if(s[a]>s[b]) e[a].push_back(b);
    }

    vector<pair<ll,ll>> p(n);
    rep(i,n) p[i] = pair<ll,ll>(s[i], i);
    sort(p.begin(), p.end());
    // s[i] 昇順に決定
    vector<ll> ans(n);
    for(auto [x, i] : p){
        for(int j : e[i]) ans[i] = max(ans[i], ans[j]);
        ans[i] += s[i];
    }

    cout << *max_element(ans.begin(), ans.end()) << endl;

}