use itertools::Itertools;
use proconio::{input, marker::Usize1};

fn main() {
    input! {
        n: usize,
        s: [usize; n],
        edges: [(Usize1, Usize1); n - 1],
    }

    let mut graph = vec![vec![]; n];
    for &(u, v) in &edges {
        if s[u] < s[v] {
            graph[u].push(v);
        } else if s[u] > s[v] {
            graph[v].push(u);
        }
    }

    let order = (0..n).sorted_unstable_by_key(|&v| s[v]).collect_vec();

    let mut dp = vec![0; n];
    let mut ans = 0;
    for &v in order.iter().rev() {
        dp[v] = s[v] + graph[v].iter().map(|&u| dp[u]).max().unwrap_or(0);
        ans = ans.max(dp[v]);
    }

    println!("{ans}");
}