#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 9;

struct Point {
    double x, y, z;
    Point() : x(0), y(0), z(0) {}
    Point(double x, double y, double z) : x(x), y(y), z(z) {}
    Point operator +(Point p) { return Point(x + p.x, y + p.y, z + p.z); }
    Point operator -(Point p) { return Point(x - p.x, y - p.y, z - p.z); }
    Point operator *(double k) { return Point(x * k, y * k, z * k); }
    Point operator /(double k) { return Point(x / k, y / k, z / k); }
    Point &operator+=(Point p) { x += p.x; y += p.y; z += p.z; return *this; }
    Point &operator-=(Point p) { x -= p.x; y -= p.y; z -= p.z; return *this; }
    Point &operator*=(double k) { x *= k; y *= k; z *= k; return *this; }
    Point &operator/=(double k) { x /= k; y /= k; z /= k; return *this; }
};

double norm(Point a) {
    return a.x * a.x + a.y * a.y + a.z * a.z;
}

double abs(Point a) {
    return sqrt(norm(a));
}

double dot(Point a, Point b) {
    return a.x * b.x + a.y * b.y + a.z * b.z;
}

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

int N;
Point P, Q[300];

pair<Point, Point> orthonormalize(Point u, Point v) {
    u /= abs(u);
    v -= u * dot(u, v);
    v /= abs(v);

    return make_pair(u, v);
}

int main() {
    cin >> N;
    cin >> P.x >> P.y >> P.z;
    rep (i, N) cin >> Q[i].x >> Q[i].y >> Q[i].z;

    double ans = 0;
    rep (i, N) rep2 (j, i + 1, N) rep2 (k, j + 1, N) {
        auto p = orthonormalize(Q[j] - Q[i], Q[k] - Q[i]);
        Point u = P - Q[i];
        u -= p.first * dot(p.first, u) + p.second * dot(p.second, u);

        ans += abs(u);
    }

    printf("%.20f\n", ans);
}