fn run<W: Write>(sc: &mut scanner::Scanner, out: &mut std::io::BufWriter<W>) {
    let t: u32 = sc.next();
    let mut dp = vec![std::cell::Cell::new(0usize); 100000 / 64 + 1];
    for _ in 0..t {
        let n: usize = sc.next();
        let w: usize = sc.next();
        let a: Vec<usize> = sc.next_vec(n);
        let ans = unsafe {solve(w, a, &mut dp)};
        writeln!(out, "{}", ans).ok();
    }
}

#[target_feature(enable = "avx2")]
unsafe fn solve(len: usize, a: Vec<usize>, dp: &mut Vec<std::cell::Cell<usize>>) -> usize {
    let w = std::mem::size_of::<usize>() * 8;
    dp.clear();
    dp.resize(len / w + 1, std::cell::Cell::new(0usize));
    dp[0].set(1);
    for a in a {
        let q = a / w;
        let r = a % w;
        if q >= dp.len() {
            continue;
        }
        if r == 0 {
            for (a, b) in dp[q..].iter().zip(dp.iter()).rev() {
                let v = b.get() | a.get();
                a.set(v);
            }
        } else {
            for ((a, b), c) in dp[q + 1..].iter().zip(dp.iter()).zip(dp[1..].iter()).rev() {
                let v = a.get() | (b.get() >> (w - r)) | (c.get() << r);
                a.set(v);
            }
            if q < dp.len() {
                let v = dp[q].get() | (dp[0].get() << r);
                dp[q].set(v);
            }
        }
    }
    let r = (len + 1) % w;
    if r != 0 {
      let v = dp[dp.len() - 1].get() & ((1 << r) - 1);
      dp[dp.len() - 1].set(v);
    }
    let x = dp.iter().rposition(|dp| dp.get() != 0).unwrap();
    w * (x + 1) - dp[x].get().leading_zeros() as usize - 1
//    (0..=len).rfind(|i| dp[i / w].get() >> (i % w) & 1 == 1).unwrap()
}

// ---------- begin scannner ----------
#[allow(dead_code)]
mod scanner {
    use std::str::FromStr;
    pub struct Scanner<'a> {
        it: std::str::SplitWhitespace<'a>,
    }
    impl<'a> Scanner<'a> {
        pub fn new(s: &'a String) -> Scanner<'a> {
            Scanner {
                it: s.split_whitespace(),
            }
        }
        pub fn next<T: FromStr>(&mut self) -> T {
            self.it.next().unwrap().parse::<T>().ok().unwrap()
        }
        pub fn next_bytes(&mut self) -> Vec<u8> {
            self.it.next().unwrap().bytes().collect()
        }
        pub fn next_chars(&mut self) -> Vec<char> {
            self.it.next().unwrap().chars().collect()
        }
        pub fn next_vec<T: FromStr>(&mut self, len: usize) -> Vec<T> {
            (0..len).map(|_| self.next()).collect()
        }
    }
}
// ---------- end scannner ----------

use std::io::Write;
use std::collections::*;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn main() {
    use std::io::Read;
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut sc = scanner::Scanner::new(&s);
    let out = std::io::stdout();
    let mut out = std::io::BufWriter::new(out.lock());
    run(&mut sc, &mut out);
}