package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"reflect"
	"sort"
	"strconv"
	"unsafe"
)

var (
	readString func() string
	readBytes  func() []byte
	stdout     *bufio.Writer
)

func init() {
	readString, readBytes = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func newReadString(ior io.Reader) (func() string, func() []byte) {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	f1 := func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
	f2 := func() []byte {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Bytes()
	}
	return f1, f2
}

func readInt() int {
	return int(readInt64())
}

func readInt64() int64 {
	i, err := strconv.ParseInt(readString(), 10, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func readFloat64() float64 {
	f, err := strconv.ParseFloat(readString(), 64)
	if err != nil {
		panic(err.Error())
	}
	return f
}

func printf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(stdout, f, args...)
}

func println(args ...interface{}) (int, error) {
	return fmt.Fprintln(stdout, args...)
}

func eprintln(args ...interface{}) (int, error) {
	return fmt.Fprintln(os.Stderr, args...)
}

func eprintf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(os.Stderr, f, args...)
}

// readString() string
// readInt() int
// readInt64() int64
// readFloat64() float64

// -----------------------------------------------------------------------------

func main() {
	defer stdout.Flush()
	N := readInt()
	K := readInt()
	mx := make(map[int]bool)
	my := make(map[int]bool)
	m := make(map[int]map[int]int)
	for i := 0; i < N; i++ {
		x := readInt()
		y := readInt()

		mx[x] = true
		my[y] = true

		m2, ok := m[x]
		if !ok {
			m2 = make(map[int]int)
			m[x] = m2
		}
		m2[y]++
	}

	xs := make([]int, 0, N)
	for x := range mx {
		xs = append(xs, x)
	}
	ys := make([]int, 0, N)
	for y := range my {
		ys = append(ys, y)
	}

	sort.Ints(xs)
	sort.Ints(ys)

	s := make([][]int, len(xs)+1)
	for i := range s {
		s[i] = make([]int, len(ys)+1)
	}

	for i := 1; i <= len(xs); i++ {
		for j := 1; j <= len(ys); j++ {
			x := xs[i-1]
			y := ys[j-1]
			s[i][j] = s[i][j-1] + m[x][y]
		}
	}

	for i := 1; i <= len(xs); i++ {
		for j := 1; j <= len(ys); j++ {
			s[i][j] += s[i-1][j]
		}
	}

	sum := func(i, j, k, l int) int {
		return s[k][l] - s[i][l] - s[k][j] + s[i][j]
	}

	inf := int64(1000000001)
	ans := 2 * inf * 2 * inf

	for i := 0; i+2 <= len(xs); i++ {
		for ie := i + 2; ie <= len(xs); ie++ {
			for j := 0; j+2 <= len(ys); j++ {
				for je := j + 2; je <= len(ys); je++ {
					if sum(i, j, ie, je) < K {
						continue
					}
					x := xs[i]
					xe := xs[ie-1]
					y := ys[j]
					ye := ys[je-1]
					ans = min(ans, int64(xe-x)*int64(ye-y))
				}
			}
		}
	}

	println(ans)
}

func min(a, b int64) int64 {
	if a < b {
		return a
	}
	return b
}

func max(a, b int64) int64 {
	if a < b {
		return b
	}
	return a
}

func abs(a int64) int64 {
	if a < 0 {
		return -a
	}
	return a
}

type Point struct {
	x, y int64
}

func (p Point) Dist2(q Point) int64 {
	return abs(q.x-p.x) * abs(q.y-p.y)
}

// -----------------------------------------------------------------------------

// =============================================================================

// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// name of functions are changed

// The function panics if the provided interface is not a slice.
func Sort(slice interface{}, less func(i, j int) bool) {
	rv := reflect.ValueOf(slice)
	swap := _sort_Swapper(slice)
	length := rv.Len()
	_sort_quickSort_func(_sort_lessSwap{less, swap}, 0, length, _sort_maxDepth(length))
}

func _sort_maxDepth(n int) int {
	var depth int
	for i := n; i > 0; i >>= 1 {
		depth++
	}
	return depth * 2
}

type _sort_lessSwap struct {
	Less func(i, j int) bool
	Swap func(i, j int)
}

// Auto-generated variant of sort.go:insertionSort
func _sort_insertionSort_func(data _sort_lessSwap, a, b int) {
	for i := a + 1; i < b; i++ {
		for j := i; j > a && data.Less(j, j-1); j-- {
			data.Swap(j, j-1)
		}
	}
}

// Auto-generated variant of sort.go:siftDown
func _sort_siftDown_func(data _sort_lessSwap, lo, hi, first int) {
	root := lo
	for {
		child := 2*root + 1
		if child >= hi {
			break
		}
		if child+1 < hi && data.Less(first+child, first+child+1) {
			child++
		}
		if !data.Less(first+root, first+child) {
			return
		}
		data.Swap(first+root, first+child)
		root = child
	}
}

// Auto-generated variant of sort.go:heapSort
func _sort_heapSort_func(data _sort_lessSwap, a, b int) {
	first := a
	lo := 0
	hi := b - a
	for i := (hi - 1) / 2; i >= 0; i-- {
		_sort_siftDown_func(data, i, hi, first)
	}
	for i := hi - 1; i >= 0; i-- {
		data.Swap(first, first+i)
		_sort_siftDown_func(data, lo, i, first)
	}
}

// Auto-generated variant of sort.go:medianOfThree
func _sort_medianOfThree_func(data _sort_lessSwap, m1, m0, m2 int) {
	if data.Less(m1, m0) {
		data.Swap(m1, m0)
	}
	if data.Less(m2, m1) {
		data.Swap(m2, m1)
		if data.Less(m1, m0) {
			data.Swap(m1, m0)
		}
	}
}

// Auto-generated variant of sort.go:doPivot
func _sort_doPivot_func(data _sort_lessSwap, lo, hi int) (midlo, midhi int) {
	m := int(uint(lo+hi) >> 1)
	if hi-lo > 40 {
		s := (hi - lo) / 8
		_sort_medianOfThree_func(data, lo, lo+s, lo+2*s)
		_sort_medianOfThree_func(data, m, m-s, m+s)
		_sort_medianOfThree_func(data, hi-1, hi-1-s, hi-1-2*s)
	}
	_sort_medianOfThree_func(data, lo, m, hi-1)
	pivot := lo
	a, c := lo+1, hi-1
	for ; a < c && data.Less(a, pivot); a++ {
	}
	b := a
	for {
		for ; b < c && !data.Less(pivot, b); b++ {
		}
		for ; b < c && data.Less(pivot, c-1); c-- {
		}
		if b >= c {
			break
		}
		data.Swap(b, c-1)
		b++
		c--
	}
	protect := hi-c < 5
	if !protect && hi-c < (hi-lo)/4 {
		dups := 0
		if !data.Less(pivot, hi-1) {
			data.Swap(c, hi-1)
			c++
			dups++
		}
		if !data.Less(b-1, pivot) {
			b--
			dups++
		}
		if !data.Less(m, pivot) {
			data.Swap(m, b-1)
			b--
			dups++
		}
		protect = dups > 1
	}
	if protect {
		for {
			for ; a < b && !data.Less(b-1, pivot); b-- {
			}
			for ; a < b && data.Less(a, pivot); a++ {
			}
			if a >= b {
				break
			}
			data.Swap(a, b-1)
			a++
			b--
		}
	}
	data.Swap(pivot, b-1)
	return b - 1, c
}

// Auto-generated variant of sort.go:quickSort
func _sort_quickSort_func(data _sort_lessSwap, a, b, maxDepth int) {
	for b-a > 12 {
		if maxDepth == 0 {
			_sort_heapSort_func(data, a, b)
			return
		}
		maxDepth--
		mlo, mhi := _sort_doPivot_func(data, a, b)
		if mlo-a < b-mhi {
			_sort_quickSort_func(data, a, mlo, maxDepth)
			a = mhi
		} else {
			_sort_quickSort_func(data, mhi, b, maxDepth)
			b = mlo
		}
	}
	if b-a > 1 {
		for i := a + 6; i < b; i++ {
			if data.Less(i, i-6) {
				data.Swap(i, i-6)
			}
		}
		_sort_insertionSort_func(data, a, b)
	}
}

// ----------------------------------------------------------------------------

func _sort_Swapper(slice interface{}) func(i, j int) {
	v := reflect.ValueOf(slice)
	vdata := v.Pointer()
	vlen := v.Len()
	vcap := v.Cap()

	sz := int(v.Type().Elem().Size())

	// for typical small elements
	switch sz {
	case 24: // for slice
		var s [][3]int64
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	case 16: // for string
		var s [][2]int64
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	case 8:
		var s []int64
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	case 4:
		var s []int32
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	case 2:
		var s []int16
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	case 1:
		var s []int8
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen
		h.Cap = vcap
		return func(i, j int) { s[i], s[j] = s[j], s[i] }
	}

	// for large elements
	if sz%16 == 0 {
		m := sz / 16
		var s [][2]int64
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen * m
		h.Cap = vcap * m
		return func(i, j int) {
			for k := 0; k < m; k++ {
				ri := i*m + k
				rj := j*m + k
				s[ri], s[rj] = s[rj], s[ri]
			}
		}
	}
	if sz%8 == 0 {
		m := sz / 8
		var s []int64
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen * m
		h.Cap = vcap * m
		return func(i, j int) {
			for k := 0; k < m; k++ {
				ri := i*m + k
				rj := j*m + k
				s[ri], s[rj] = s[rj], s[ri]
			}
		}
	}
	if sz%4 == 0 {
		m := sz / 4
		var s []int32
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen * m
		h.Cap = vcap * m
		return func(i, j int) {
			for k := 0; k < m; k++ {
				ri := i*m + k
				rj := j*m + k
				s[ri], s[rj] = s[rj], s[ri]
			}
		}
	}
	if sz%2 == 0 {
		m := sz / 2
		var s []int16
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen * m
		h.Cap = vcap * m
		return func(i, j int) {
			for k := 0; k < m; k++ {
				ri := i*m + k
				rj := j*m + k
				s[ri], s[rj] = s[rj], s[ri]
			}
		}
	} else {
		m := sz
		var s []int8
		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
		h.Data = vdata
		h.Len = vlen * m
		h.Cap = vcap * m
		return func(i, j int) {
			for k := 0; k < m; k++ {
				ri := i*m + k
				rj := j*m + k
				s[ri], s[rj] = s[rj], s[ri]
			}
		}
	}
}

// =============================================================================


Measured memory_bytes: 640