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::().unwrap(); for _ in 0..t { run(); } }