import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
import java.util.Scanner;
class areacircle
{
public static void main (string args[])
{
float r ,area;
scanner o=new Scanner (system.in);
system.out.printin("enter r");
r=o.nextfloat();
area=3.14f*r*r;
    //area=(float)3.14*r*r;
    ystem.out.printin("area is:"+area);
}
}