#include <bits/stdc++.h>
using namespace std;

#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define ALL(x) (x).begin(), (x).end()
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
#define fst first
#define snd second
typedef long long ll;
typedef vector<int> vi;typedef vector<vi> vvi;typedef pair<int,int> pii;typedef vector<pii> vpii;

struct P3D {
  double x, y, z;
  P3D() : x(0), y(0), z(0) {};
  P3D(double x, double y, double z) : x(x), y(y), z(z) {};
};

P3D sub(const P3D &a, const P3D &b) {
  P3D ret(a.x-b.x, a.y-b.y, a.z-b.z);
  return ret;
}

P3D cross(const P3D &a, const P3D &b) {
  P3D ret(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
  return ret;
}

double distance(const P3D &p, const P3D &a, const P3D &b, const P3D &c) {
  P3D ab = sub(a, b);
  P3D ac = sub(a, c);
  P3D h = cross(ab, ac);
  double d = h.x * -a.x + h.y * -a.y + h.z * -a.z;
  double si = fabs(h.x * p.x + h.y * p.y + h.z * p.z + d);
  double bo = sqrt(h.x * h.x + h.y * h.y + h.z * h.z);
  return si / bo;
}

void Main() {
  int N;
  cin >> N;
  P3D p;
  cin >> p.x >> p.y >> p.z;

  vector<P3D> Q(N);
  rep(i, N) {
    cin >> Q[i].x >> Q[i].y >> Q[i].z;
  }

  double ans = 0;

  rep(i, N) {
    rep(j, i+1, N) {
      rep(k, j+1, N) {
        P3D &a = Q[i];
        P3D &b = Q[j];
        P3D &c = Q[k];
        double D = distance(p, a, b, c);
        ans += D;
      }
    }
  }
  _p("%.20f\n", ans);
}
int main() { cin.tie(0); ios::sync_with_stdio(false); Main(); return 0; }