#include #pragma GCC optimize("Ofast") //#pragma GCC target("avx2") #pragma GCC optimize("unroll-loops") using namespace std; //#include //#include //namespace mp=boost::multiprecision; //#define mulint mp::cpp_int //#define mulfloat mp::cpp_dec_float_100 struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<=0;(i)--) #define flc(x) __builtin_popcountll(x) #define pint pair #define pdouble pair #define plint pair #define fi first #define se second #define all(x) x.begin(),x.end() #define vec vector #define nep(x) next_permutation(all(x)) typedef long long lint; int dx[8]={1,1,0,-1,-1,-1,0,1}; int dy[8]={0,1,1,1,0,-1,-1,-1}; const int MAX_N=3e5+5; templatebool chmax(T &a,const T &b){if(abool chmin(T &a,const T &b){if(b bucket[MAX_N/1000]; constexpr int MOD=1000000007; //constexpr int MOD=998244353; /*#include using namespace atcoder; typedef __int128_t llint;*/ int main(void){ int T; cin >> T; while(T--){ double r; cin >> r; double ans = pow(3,1.5)*r*r/4; cout << ans << endl; } }