How high would presidential nominees' unfavorability ratings have to be to mathematically guarantee that the majority of the country does not support either candidate?

We are facing the highly unusual prospect of having the nominees of both parties being disliked by a majority of the population. Link

That inspired the following simple math problem. Assuming that the p is the percentage of people who dislike Trump and p is also the percent of people dislike Clinton, and assuming everyone votes, how high would p have to be before we could conclude that the majority of voters ended up voting for someone they dislike?