T = gets.to_i

def send_query(y)
  STDOUT.puts("? %.12f" % y)
  STDOUT.flush

  res = gets.chomp
  res == "Yes"
end

T.times do
  ok = 0
  ng = 76.0

  24.times do
    e = (ok + ng) / 2.0
    y = 10 ** e - 1.0

    if send_query(y)
      ok = e
    else
      ng = e
    end
  end

  STDOUT.puts("! %.12f" % (10 ** ok - 1.0))
  STDOUT.flush
end