import math

T = int(input())

while T >= 0:
    T-=1
    ok = 5*(10**-6)
    ng = 12.22*(10**74)
    for i in range(24):
        mid = math.exp((math.log(ok) + math.log(ng)) / 2)
        print("? {:.10f}".format(mid), flush=True)
        ans = input()
        if ans == "Yes":
            ok = mid
        else:
            ng = mid

    print("{:.10f}".format(ok))