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

template<typename T>
struct Vector3 {
	T x,y,z;
	Vector3 operator+(const Vector3 &v) {
		return { x + v.x, y + v.y, z + v.z };
	}
	Vector3 operator-(const Vector3 &v) {
		return { x - v.x, y - v.y, z - v.z };
	}
	T dot(const Vector3 &v) {
		return  x * v.x + y * v.y + z * v.z;
	}
	Vector3 cross(Vector3 v) {
		return {
			y * v.z - z * v.y,
			z * v.x - x * v.z,
			x * v.y - y * v.x
		};
	}
	T abs() {
        return sqrt(x * x + y * y + z * z);
    }
};
int main() {
    #ifdef DEBUG
    std::ifstream in("/home/share/inputf.in");
    std::cin.rdbuf(in.rdbuf());
    #endif
    int N;
    cin >> N;
    Vector3<double> P;
    vector<Vector3<double>> V(N);
    cin >> P.x >> P.y >> P.z;
    for(int i = 0; i < N; i++) {
        cin >> V[i].x >> V[i].y >> V[i].z;
    }
    double ans = 0;
    // O(N^3)
    for(int i = 0; i < N; i++) {
        for(int j = i + 1; j < N; j++) {
            Vector3<double> v1 = V[j] - V[i];
            for(int k = j + 1; k < N; k++) {
                Vector3<double> norm = v1.cross(V[k] - V[i]);
                ans += abs(norm.dot(P) - norm.dot(V[i])) / norm.abs();
            }
        }
    }
    cout << std::fixed << std::setprecision(15) << ans << endl;
    return 0;
}