A mad scientist has captured you and is showing you around his foul-smelling laboratory. He motions to an opaque, formalin-filled jar. "This jar contains one organ, either a kidney or a brain," he cheerily informs you. His voice seems an octave too high as he gives you a twisted leer. You watch as the madman grabs a brain lying on his worktable and drops it into the jar as well. He then shakes the jar and quickly withdraws a single organ. It proves to be a brain. He turns to you and says, "What is now the chance of removing another brain?" Fearing that the scientist might remove your brain in his next ghoulish experiment, you want to give him the right answer. What is your response?† (Enter the probability as a fraction.)