#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int main() {
	long double x = 1.299038105676657;
	int t;
	cin >> t;
	for (int i = 0; i < t; i++) {
		long double r;
		cin >> r;
		cout << fixed << setprecision(16) << x * r * r << endl;
	}
}