Problem:
Score : 100 points

Problem Statement

Given an integer N not less than 3, find the sum of the interior angles of a regular polygon with N sides.

Print the answer in degrees, but do not print units.

Constraints

3 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print an integer representing the sum of the interior angles of a regular polygon with N sides.

Sample Input 1

3

Sample Output 1

180

The sum of the interior angles of a regular triangle is 180 degrees.

Sample Input 2

100

Sample Output 2

17640

Solution in Ruby (2.3.3) (judge verdict: Accepted)

def takakkei
  loop do
    i = 180
    y = 2
    
    n = $stdin.gets.chomp.to_i
    
    return i * ( n - y )
  end
end
puts takakkei