inputarea

import java.util.Scanner;

/*
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 */


/**
 *
 * @author cse
 */
public class NewInput {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc;
        sc= new Scanner(System.in);
        int n= sc.nextInt();

        System.out.println(n);
        for(int i=1; i<=n; i++)
        {
           int r= sc.nextInt();
           double area= 3.1416*r*r;
           System.out.println(area);


        }
    }
}