#include <stdio.h>
#include <math.h>
#define pi 3.1415926
int main (void) {
int a,c;
double b,d;
scanf("%d",&a);
for (c=0;c<a;c++)
{
scanf("%lf",&b);
d=sqrt(pow(b,2)-pow(b/2.0,2))*2.0/3.0;
printf("%.2lf\n",pi*pow(d,2));
}
return 0;
}
#include <math.h>
#define pi 3.1415926
int main (void) {
int a,c;
double b,d;
scanf("%d",&a);
for (c=0;c<a;c++)
{
scanf("%lf",&b);
d=sqrt(pow(b,2)-pow(b/2.0,2))*2.0/3.0;
printf("%.2lf\n",pi*pow(d,2));
}
return 0;
}