fn read() -> String { let mut s = String::new(); std::io::stdin().read_line(&mut s).unwrap(); String::from(s.trim()) } fn run() { let mut l = 10f64.powi(-5); let mut r = 12.22f64 * 10f64.powi(74); for _ in 0..24 { let m = (l * r).sqrt(); println!("? {}", m); let ans = read(); match ans.as_str() { "Yes" => l = m, "No" => r = m, _ => unreachable!(), } } let m = (l * r).sqrt(); let abs = (m - l).abs().max((r - m).abs()) <= 1e-5; let re = r - m <= 1e-5 * r && m - l <= 1e-5 * l; assert!(abs || re); println!("! {}", (l * r).sqrt()); } fn main() { let t = read().parse::().unwrap(); for _ in 0..t { run(); } }