International Olympiad#11021
The International Olympiad in Informatics has been held every year since 1989.
At the first olympiad in 1989, there was only one round with one problem.
For the next three years (1990-1992), the olympiad was held in two rounds, with one problem in each round.
In 1993, there were two rounds. The first round had three problems, and the second had only one.
Starting from 1994, the olympiad has had two rounds, with three problems in each round. The only exceptions are the years 2009 and 2010, in which each round had four problems.
Given the year of the International Olympiad in Informatics, determine the number of problems that were at that olympiad.
The first line contains one integer (1989 \leq n \leq 2021).
Output one integer — the number of problems.
Example 1
Example 2
Example 3