import java.util.*;

public class Main{
  
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int t = sc.nextInt();
    
    for(int i=0; i<t; i++){
      
      int r = sc.nextInt();
      double ans = 1.299038105676657*r*r;
      
      System.out.println(ans);
      
    }
  
  }

}