I was going to ask how they would check if the answer is correct, because they too would need "35 years" to find it... ... but then I realized that N is a prod

I was going to ask how they would check if the answer is correct, because they too would need "35 years" to find it... ... but then I realized that N is a product of two primes, which Rivest knows, so he can take a shortcut and compute the answer faster. That is, the answer is known. But this makes you wonder if factoring that N would've been a faster route to solving this puzzle. What do you guys think? [1] https://people.csail.mit.edu/rivest/lcs35-puzzle-description.txt https://people.csail.mit.edu/rivest/lcs35-puzzle-description...