fn is_kadomatsu((a, b, c): (usize, usize, usize)) -> bool {
    if a == b || b == c || c == a { return false; }
    (a > b && b < c) || (a < b && b > c)
}

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];
        for i in start..n-2+start {
            let target = (a[i%n], a[(i+1)%n], a[(i+2)%n]);
            let p0 = if i == 0 { 0 } else { dp[i-1][0] };
            let p1 = if i < 3 { 0 } else { dp[i-3][1] };
            dp[i][0] = dp[i][0].max(p0).max(p1);
            let val = if is_kadomatsu(target) { target.0 } else { 0 };
            dp[i][1] = dp[i][1].max(p0+val).max(p1+val);
        }
        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);
    }
}