import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
double length = keyboard.nextDouble();
double s=2*length*Math.sin(Math.PI/5);
double area=5*Math.pow(s,2)/4/Math.tan(Math.PI/5);
double areas=Math.floor(area*100)/100;
System.out.println(areas);
}
}
intelij에서는 실행되는데 wrong answer라고 떠요..
뭐가틀렸을까요??ㅜㅜ
