#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <cmath>
#include <cassert>
#include <tuple>
#define rep(i, n) for(i = 0; i < n; i++)
#define int long long
using namespace std;

signed main() {
	int t;
	cin >> t;
	while (t--) {
		double r;
		cin >> r;
		double ans = 1.299038105676657 * r * r;
		printf("%.14f\n", ans);
	}
	return 0;
}