Suppose you face a gamble such that you can win $Y with 50% chance, or lose $Y/2 with 50% chance. You assessed that the maximum acceptable Y is $1,000. You are a risk-averse behavior and your preference can be modeled with an exponential utility function. What is the utility function after affine transformation, so that U($100) = 0 and U($5,000) = 1?