You are in a market where you can invest in a stock or bet at a casino in increments. Call these increments units. Note that you may not purchase fractions of a unit. If you invest in the stock, then it goes up or down. If it goes up in value, you gain an additional dollars per unit. If it goes down, you lose dollars per unit. Additionally, you can bet on whether the stock will go up or down at the casino, where you either win per unit if you're right or lose all if not. Devise a strategy where you will always make a profit. Find the guaranteed profit if you hold a minimal amount of total units.