Q: Passage: The 2017 Tour de France is the 104th edition of the race, one of cycling's Grand Tours. The 21-stage race takes place from 1 July to 23 July 2017, starting in Dusseldorf in Germany and finishing on the Champs-Elysees in Paris. All eighteen Union Cycliste Internationale (UCI) WorldTeams were automatically invited and were obliged to attend the race. Four UCI Professional Continental teams were given wildcard places into the race by the organiser -- Amaury Sport Organisation (ASO) -- to complete the 22-team peloton. As each team is entitled to enter nine riders, the peloton on the first stage consists of 198 riders from 32 countries.

Question: Based on this passage, number of participating countries in tour de france 2017? Let's give stream of consciousness first:
To answer the above question, the relevant sentence is: As each team is entitled to enter nine riders, the peloton on the first stage consists of 198 riders from 32 countries. Therefore, the final answer is 32.