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

// TLE

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

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

    ll ans = 0;
    rep(r,n) if(fl[r]){
        vector<ll> dp(n);
        dp[r] = s[r];
        queue<int> q;
        q.push(r);
        while(q.size()){
            int f = q.front(); q.pop();
            for(int t : e[f]) if(s[f]<s[t]){
                dp[t] = dp[f]+s[t];
                q.push(t);
            }
        }
        rep(i,n) if(ans<dp[i]) ans = dp[i];
    }

    cout << ans << endl;

}