If you advertise and your rival advertises, you each will earn $4 million in profits. If neither of you advertises, you will each earn $10 million in profits. However, if one of you advertises and the other does not, the firm that advertises will earn $1 million and the non-advertising firm will earn $5 million. Suppose this game is repeated for a finite number of times, but the players do not know the exact date at which the game will end. The players can earn profits of $10 each period as a Nash equilibrium to a repeated play of the game if the probability the game terminates at the end of any period is: