Answer: 17.

Solution: As "Raritet" departs from Lviv, a steamer arrives there, which left Dzerzhinsk 8 days ago. By the time "Raritet" arrives at its final destination, 8 days have passed since the initial moment, and at this moment, the last steamer departs from Dzerzhinsk, which "Raritet" meets on its way. Thus, "Raritet" will meet all the steamers that departed from Dzerzhinsk, starting 8 days before the initial time and ending 8 days after the initial time - a total of 17 steamers (if it is considered that the ships meet when one departs and the other arrives at the same moment).

Criteria: only the answer, answer with verification - 0 points.

If it is considered that "Raritet" does not meet the first and/or last steamers - do not deduct points.
8.3. There is a steamship route between the cities of Dzerzhinsk and Lviv. Every midnight, a steamship departs from Dzerzhinsk, arriving exactly eight days later in Lviv. How many steamships will the steamship "Raritet" meet on its way to Dzerzhinsk if it departs from Lviv exactly at midnight and spends the same eight days on the journey?