#include <bits/stdc++.h>
using namespace std;
#define rep(i,l,r) for(int i=(l);i<(r);++i)
typedef long long ll;
const double PI = acos(-1);

int main(){
	int n; cin>>n;
	rep(i,0,n){
		double r; cin>>r;
		cout<<r*r*(3*sqrt(3)/4)<<endl;
	}
}