fn read() -> String {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    String::from(s.trim())
}

fn run() {
    let m = 10f64.powi(-5) * 2f64.powi(23);
    println!("? {}", m);
    let ans = read();
    if ans.as_str() == "Yes" {
        let mut l = 1f64.powi(-5);
        let mut r = m;
        for _ in 0..24 {
            let m = (l + r) * 0.5;
            println!("? {}", m);
            let ans = read();
            match ans.as_str() {
                "Yes" => r = m,
                "No" => l = m,
                _ => unreachable!(),
            }
        }
        println!("! {}", (l + r) * 0.5);
    } else {
        let mut l = m;
        let mut r = 12.22e74;
        for _ in 0..24 {
            let m = (l * r).sqrt();
            println!("? {}", m);
            let ans = read();
            match ans.as_str() {
                "Yes" => r = m,
                "No" => l = m,
                _ => unreachable!(),
            }
        }
        println!("! {}", (l * r).sqrt());
    }
}

fn main() {
    let t = read().parse::<u32>().unwrap();
    for _ in 0..t {
        run();
    }
}