fn is_kadomatsu(a: &Vec<usize>) -> bool {
    a[0] != a[1] && a[1] != a[2] && a[2] != a[0]
    && (*a.iter().min().unwrap() == a[1] || *a.iter().max().unwrap() == a[1])
}

fn solve() -> usize {
    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<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let mut result = 0usize;
    for start in 0..3 {
        let mut dp = vec![vec![0usize; 2]; n+1];
        for i in start..n+start-2 {
            let aval = a[i];
            let target = vec![aval, a[(i+1)%n], a[(i+2)%n]];
            let kadoval = if is_kadomatsu(&target) { aval } else { 0 };
            dp[i+1][0] = dp[i][0];
            dp[i+1][1] = dp[i][0] + kadoval;
            if i >= 2 {
                dp[i+1][0] = dp[i+1][0].max(dp[i-2][1]);
                dp[i+1][1] = dp[i+1][1].max(dp[i-2][1] + kadoval)
            }
        }
        result = result.max(dp.iter().map(|v| *v.iter().max().unwrap()).max().unwrap());
    }
    result
}

fn main() {
    let mut t = String::new();
    std::io::stdin().read_line(&mut t).ok();
    let t: usize = t.trim().parse().unwrap();
    let mut result = Vec::with_capacity(t);
    for _ in 0..t {
        result.push(solve());
    }
    for &v in result.iter() {
        println!("{}", v);
    }
}