fn dfs(cur: usize, prev: usize, a: &Vec<isize>, b: &Vec<isize>, paths: &Vec<Vec<usize>>, dp: &mut Vec<Vec<isize>>) {
    let mut used = 0isize;
    let mut unused = 0isize;
    for &v in paths[cur].iter() {
        if v == prev { continue; }
        dfs(v, cur, a, b, paths, dp);
        used += dp[v][0].max(dp[v][1] + b[v] + b[cur]);
        unused += dp[v][0].max(dp[v][1]);
    }
    dp[cur][0] = unused + a[cur];
    dp[cur][1] = used;
}

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<isize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let mut b = String::new();
    std::io::stdin().read_line(&mut b).ok();
    let b: Vec<isize> = b.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let mut paths = vec![vec![]; n];
    for _ in 0..n-1 {
        let mut temp = String::new();
        std::io::stdin().read_line(&mut temp).ok();
        let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let u = temp[0]-1;
        let v = temp[1]-1;
        paths[u].push(v);
        paths[v].push(u);
    }

    let mut dp = vec![vec![0isize; 2]; n];
    dfs(0, 0, &a, &b, &paths, &mut dp);
    println!("{}", dp[0].iter().max().unwrap());
}