using System;
using System.Collections.Generic;
using static Assistant.Input;
using static Assistant.Debug;
using System.Linq;
using Assistant;

namespace ABC075D
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = RInt;
            var K = RInt;

            //座標圧縮
            var x1 = new List<long>();
            var y1 = new List<long>();

            for (int i = 0; i < N; i++)
            {
                x1.Add(RInt);
                y1.Add(RInt);
            }

            var toValueX = x1.Distinct().OrderBy(x => x).ToArray();
            var toValueY = y1.Distinct().OrderBy(x => x).ToArray();

            var indexFromValueTableX = toValueX.Select((value, index) => new { value, index }).ToDictionary(p => p.value, p => p.index);
            var indexFromValueTableY = toValueY.Select((value, index) => new { value, index }).ToDictionary(p => p.value, p => p.index);

            int countX = indexFromValueTableX.Count;
            int countY = indexFromValueTableY.Count;

            var x2 = x1.Select(v => indexFromValueTableX[v]).ToArray();
            var y2 = y1.Select(v => indexFromValueTableY[v]).ToArray();

            int[,] map = new int[countX, countY];
            for (int i = 0; i < N; i++)
            {
                map[x2[i], y2[i]]++;
            }

            Draw2D(map);

            //O(N^5)バージョン
            long ans = long.MaxValue;
            for (int i = 0; i < countX; i++)
            {
                for (int j = 0; j < countY; j++)
                {
                    for (int k = i; k < countX; k++)
                    {
                        for (int l = j; l < countY; l++)
                        {
                            int count = 0;
                            for (int m = 0; m < N; m++)
                            {
                                if (toValueX[i] <= x1[m] && x1[m] <= toValueX[k] && toValueY[j] <= y1[m] & y1[m] <= toValueY[l]) count++;
                            }
                            if (count < K) continue;

                            long area = (toValueX[k] - toValueX[i]) * (toValueY[l] - toValueY[j]);
                            ans = Math.Min(ans, area);
                        }
                    }
                }
            }

            Console.WriteLine(ans);
        }


    }


}

namespace Assistant
{
    static class Input
    {
        static List<string> line = new List<string>();
        static int index = 0;
        static String RNext()
        {
            if (line.Count <= index) line.AddRange(Console.ReadLine().Split());
            return line[index++];
        }
        public static int RInt => int.Parse(RNext());
        public static long RLong => long.Parse(RNext());
        public static int[] RInts => Console.ReadLine().Split().Select(int.Parse).ToArray();
        public static long[] RLongs => Console.ReadLine().Split().Select(long.Parse).ToArray();
        public static string RString => RNext();
        //以下未テスト
        public static int[] RIntsC(int c) => Enumerable.Repeat(0, c).Select(x => int.Parse(RNext())).ToArray();
        public static long[] RLongsC(int c) => Enumerable.Repeat(0, c).Select(x => long.Parse(RNext())).ToArray();
        public static char[][] RMap(int h) => Enumerable.Repeat(0, h).Select(x => Console.ReadLine().ToCharArray()).ToArray();
    }

    public struct Mlong
    {
        long _v;
        const long mod = 1000000007;
        public Mlong(long n = 0) : this() { _v = n >= mod ? n % mod : n; }

        public static implicit operator Mlong(long _x) => new Mlong(_x);
        public static implicit operator long(Mlong _x) => _x._v;
        public static Mlong operator +(Mlong m1, Mlong m2) { long m = m1._v + m2._v; return m >= mod ? m - mod : m; }
        public static Mlong operator -(Mlong m1, Mlong m2) { long m = m1._v - m2._v; return m >= 0 ? m : m + mod; }
        public static Mlong operator *(Mlong m1, Mlong m2) => m1._v * m2._v % mod;
        public static Mlong operator /(Mlong m1, Mlong m2) => m1._v * ModPow(m2._v, mod - 2) % mod;

        public static long ModPow(long a, long n)
        {
            if (n == 0) return 1;
            else if (n % 2 == 1) return a * ModPow(a, n - 1) % mod;
            else return ModPow(a * a % mod, n / 2);
        }

        static Mlong[] fac, finv, inv;
        public static void nCkInit(int max)
        {
            fac = new Mlong[max]; finv = new Mlong[max]; inv = new Mlong[max];
            fac[0] = fac[1] = 1;
            finv[0] = finv[1] = 1;
            inv[1] = 1;
            for (int i = 2; i < max; i++)
            {
                fac[i] = fac[i - 1] * i;
                inv[i] = mod - inv[mod % i] * (mod / i);
                finv[i] = finv[i - 1] * inv[i];
            }
        }

        public static Mlong nCk(int n, int k)
        {
            if (n < k) return 0;
            if (n < 0 || k < 0) return 0;
            return fac[n] * finv[k] * finv[n - k];
        }
    }

    static class Debug
    {
        static public void Draw2D<T>(T[,] map, int mode = 1)
        {
#if DEBUG
            int W = map.GetLength(0);
            int H = map.GetLength(1);

            string[,] map2 = new string[W + 1, H + 1];
            for (int i = 0; i < W + 1; i++)
            {
                for (int j = 0; j < H + 1; j++)
                {
                    if (i == 0 && j == 0) map2[i, j] = 0.ToString();
                    else if (i == 0) map2[i, j] = (j - 1).ToString();
                    else if (j == 0) map2[i, j] = (i - 1).ToString();
                    else map2[i, j] = map[i - 1, j - 1].ToString();
                }
            }

            for (int i = 0; i < W + 1; i++)
            {
                for (int j = 0; j < H + 1; j++)
                {
                    if (mode == 0) Console.Write(map2[i, j].Last());
                    if (mode == 1) Console.Write(map2[i, j] + " ");
                }
                Console.WriteLine();
            }
            Console.WriteLine();
#endif
        }

        public static void Draw1D<T>(T[] array, int mode = 0)
        {
#if DEBUG
            Console.WriteLine(string.Join(" ", array));
#endif
        }
    }
}


Measured memory_bytes: 28556