using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using StringBuilder = System.Text.StringBuilder;
using System.Numerics;
namespace Program
{

    public class Solver
    {
        public void Solve()
        {
            var n = sc.Integer();
            var p = new Point(sc.Double(), sc.Double(), sc.Double());
            var ps = Enumerate(n, x => new Point(sc.Double(), sc.Double(), sc.Double()));
            var 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 += Geometry.GetDistance(p, ps[i], ps[j], ps[k]);
            IO.Printer.Out.WriteLine(ans);

        }
        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region Ex
namespace Program.IO
{
    using System.IO;
    using System.Text;
    using System.Globalization;
    public class Printer : StreamWriter
    {
        static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; }
        public static Printer Out { get; set; }
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
        public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
        public void Write<T>(string format, IEnumerable<T> source) { base.Write(format, source.OfType<object>().ToArray()); }
        public void WriteLine<T>(string format, IEnumerable<T> source) { base.WriteLine(format, source.OfType<object>().ToArray()); }
    }
    public class StreamScanner
    {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read()
        {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; }

        public string Scan()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public long Long()
        {
            if (isEof) return long.MinValue;
            long ret = 0; byte b = 0; var ng = false;
            do b = read();
            while (b != '-' && (b < '0' || '9' < b));
            if (b == '-') { ng = true; b = read(); }
            for (; true; b = read())
            {
                if (b < '0' || '9' < b)
                    return ng ? -ret : ret;
                else ret = ret * 10 + b - '0';
            }
        }
        public int Integer() { return (isEof) ? int.MinValue : (int)Long(); }
        public double Double() { return double.Parse(Scan(), CultureInfo.InvariantCulture); }
        private T[] enumerate<T>(int n, Func<T> f)
        {
            var a = new T[n];
            for (int i = 0; i < n; ++i) a[i] = f();
            return a;
        }

        public char[] Char(int n) { return enumerate(n, Char); }
        public string[] Scan(int n) { return enumerate(n, Scan); }
        public double[] Double(int n) { return enumerate(n, Double); }
        public int[] Integer(int n) { return enumerate(n, Integer); }
        public long[] Long(int n) { return enumerate(n, Long); }
    }
}

static class Ex
{
    static public string AsString(this IEnumerable<char> ie) { return new string(System.Linq.Enumerable.ToArray(ie)); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") { return string.Join(st, ie); }
    static public void Main()
    {
        var solver = new Program.Solver();
        solver.Solve();
        Program.IO.Printer.Out.Flush();
    }
}
#endregion

public struct Point
{
    public double x, y, z;
    public Point(double a, double b, double c) : this() { x = a; y = b; z = c; }
}
static public partial class Geometry
{
    static public Point Cross(Point u, Point v)
    {
        var a = u.y * v.z - v.y * u.z;
        var b = u.z * v.x - v.z * u.x;
        var c = u.x * v.y - v.x * u.y;
        return new Point(a, b, c);
    }
    static public double GetDistance(Point p, Point a, Point b, Point c)
    {
        var s = GetSurface(a, b, c);
        var u = Math.Abs(s[0] * p.x + s[1] * p.y + s[2] * p.z + s[3]);
        var v = Math.Sqrt(s[0] * s[0] + s[1] * s[1] + s[2] * s[2]);
        return u / v;
    }
    static public double[] GetSurface(Point p, Point q, Point r)
    {
        var pq = new Point(q.x - p.x, q.y - p.y, q.z - p.z);
        var pr = new Point(r.x - p.x, r.y - p.y, r.z - p.z);
        var v = Cross(pq, pr);
        return new double[] { v.x, v.y, v.z, -(v.x * p.x + v.y * p.y + v.z * p.z) };
    }
}