关于一道逻辑假设题的取反

杨枝甘鹿

Without the incentives offered by federal income tax laws, at leastsome wealthy individuals would not donate as much money to charitable andeducational institutions as they otherwise would have.

请问这个选项取反是 对at least 取反还是 would not 还是两个地方都需要取反，我绕晕了