#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
// using namespace atcoder;
// using mint = modint1000000007;
// const int mod = 1000000007;
// using mint = modint998244353;
// const int mod = 998244353;
// const int INF = 1e9;
// const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i, l, r) for (int i = (l); i < (r); ++i)
#define rrep(i, n) for (int i = (n)-1; i >= 0; --i)
#define rrep2(i, l, r) for (int i = (r)-1; i >= (l); --i)
#define all(x) (x).begin(), (x).end()
#define allR(x) (x).rbegin(), (x).rend()
#define P pair<int, int>
template<typename A, typename B> inline bool chmax(A& a, const B& b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A& a, const B& b) { if (a > b) { a = b; return true; } return false; }

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int n; cin >> n;
	vector<int>s(n);
	rep(i, n)cin >> s[i];
	vector g(n, vector<int>());
	rep(i, n - 1) {
		int a, b; cin >> a >> b;
		a--, b--;
		if (s[a] > s[b])g[b].push_back(a);
		if (s[b] > s[a])g[a].push_back(b);
	}
	priority_queue<pair<long long, int>>pq;
	vector<long long>dp(n);
	rep(i, n) {
		dp[i] = s[i];
		pq.emplace(dp[i], i);
	}
	while (!pq.empty()) {
		auto [val, idx] = pq.top();
		pq.pop();
		if (dp[idx] != val)continue;

		for (auto nidx : g[idx]) {
			if (chmax(dp[nidx], dp[idx] + s[nidx])) {
				pq.emplace(dp[nidx], nidx);
			}
		}
	}
	long long ans = 0;
	rep(i, n)chmax(ans, dp[i]);
	cout << ans << endl;
	return 0;
}