Bob proposes a game to Alice: Each of them are given a coin that they are allowed to decide the probability of heads for. Let and be the probabilities that Alice and Bob select, respectively. They both flip their coins. If both coins come up heads, Alice gives Bob . If both come up tails, Alice gives Bob . Otherwise, if there is one head and one tail, Bob gives Alice . Find the smallest value of that Bob can select such that he still has non-positive expected value when .