#include <stdio.h>

void main(void) {
	int t = 0;
	scanf("%d",&t);
	const double equilateralTriangle = 1.299038105676657; 
	int numList[t];
	for(int i = 0;i < t ; i++){
		scanf("%d",&numList[i]);
	}
	for(int i = 0;i < t ; i++){
		printf("%0.15f\n",equilateralTriangle*numList[i]*numList[i]);
	}
}