import java.util.Scanner

object Main {
  def main(args: Array[String]): Unit = {
    //nextLineとnextを同時に使ったら死ぬ
    val sc = new Scanner(System.in)

    val n = sc.nextInt()
    println((n - 2) * 180)

  }
  def debug(args: Any*): Unit = {
    Console.err.println(args.mkString(" "))
  }
}
