T=int(input()) for t in range(T): l=1e-6 r=12.22*1e74 for _ in range(24): mid=(l*r)**.5 print(f"? {mid:.12f}") S=input() assert S!="-1" if S=="Yes": l=mid elif S=="No": r=mid else: exit() ans=(l*r)**.5 print(f"! {ans:.12f}")