264
Your representation is correct. The innkeeper considers that you can take 1 Rest for free at his inn, and some customers offer you 1d6-2 Coins (minimum 0). If you are in an inn, return to 253, and if you are in a tavern (which also serves as an inn), return to 503. If you are in a more memorable establishment, return to the Memorized number.
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An anecdote to pass the time:
Whenever there is a riddle, there is always a way to find the solution. Yet in some cases, even the author has forgotten the answer…