#include <bits/stdc++.h>

using namespace std;

struct P {
	double x;
	double y;
	double z;
	P() : x(0), y(0), z(0) {}
	P(double x, double y, double z) : x(x), y(y), z(z) {}
	P operator-(const P& p) const {
		return P(x - p.x, y - p.y, z - p.z);
	}
};

int n;
P p;
vector<P> q;

P cross(P a, P b) {
	P res;
	res.x = a.y * b.z - a.z * b.y;
	res.y = a.z * b.x - a.x * b.z;
	res.z = a.x * b.y - a.y * b.x;
	return res;
}

double dist(int i, int j, int k) {
	P a = q[j] - q[i], b = q[k] - q[i];
	P c = cross(a, b);
	double d = -c.x * q[i].x - c.y * q[i].y - c.z * q[i].z;
	double res = abs(c.x * p.x + c.y * p.y + c.z * p.z + d);
	res /= sqrt(c.x * c.x + c.y * c.y + c.z * c.z);
	return res;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cin >> n >> p.x >> p.y >> p.z;
	q.resize(n);
	for (int i = 0; i < n; i++) cin >> q[i].x >> q[i].y >> q[i].z;
	double ans = 0.0;
	for (int i = 0; i < n; i++) {
		for (int j = i + 1; j < n; j++) {
			for (int k = j + 1; k < n; k++) {
				ans += dist(i, j, k);
			}
		}
	}
	cout << fixed << setprecision(10) << ans << endl;
	return 0;
}