Story of Hyun

import java.util.Scanner;

class ScannerEx 

{

public static void main(String[] args) 

{

Scanner input=new Scanner(System.in);

System.out.print("반지름=");

double r=input.nextDouble();

double c=r*r*Math.PI; // 3.14;

System.out.println("원의 넓이="+c);

}

}