/*
URL:
https://atcoder.jp/contests/abc116/tasks/abc116_d
*/

package main

import (
	"bufio"
	"container/heap"
	"errors"
	"fmt"
	"io"
	"math"
	"os"
	"sort"
	"strconv"
)

/********** FAU standard libraries **********/

//fmt.Sprintf("%b\n", 255) 	// binary expression

/********** I/O usage **********/

//str := ReadString()
//i := ReadInt()
//X := ReadIntSlice(n)
//S := ReadRuneSlice()
//a := ReadFloat64()
//A := ReadFloat64Slice(n)

//str := ZeroPaddingRuneSlice(num, 32)
//str := PrintIntsLine(X...)

/*******************************************************************/

const (
	// General purpose
	MOD          = 1000000000 + 7
	ALPHABET_NUM = 26
	INF_INT64    = math.MaxInt64
	INF_BIT60    = 1 << 60
	INF_INT32    = math.MaxInt32
	INF_BIT30    = 1 << 30
	NIL          = -1

	// for dijkstra, prim, and so on
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

func init() {
	// bufio.ScanWords <---> bufio.ScanLines
	ReadString = newReadString(os.Stdin, bufio.ScanWords)
	stdout = bufio.NewWriter(os.Stdout)
}

var (
	n, k int
	T, D []int

	memo [100000 + 50][]int
)

func main() {
	n, k = ReadInt2()
	for i := 0; i < n; i++ {
		t, d := ReadInt2()
		T = append(T, t)
		D = append(D, d)
	}

	for i := 0; i < n; i++ {
		memo[T[i]] = append(memo[T[i]], D[i])
	}
	for i := 1; i <= n; i++ {
		sort.Sort(sort.Reverse(sort.IntSlice(memo[i])))
	}

	tops, others := NewTopSushiPQ(), NewOtherSushiPQ()
	for i := 1; i <= n; i++ {
		if len(memo[i]) >= 1 {
			tops.push(&TopSushi{pri: memo[i][0], kind: i})
		}

		for j := 1; j < len(memo[i]); j++ {
			others.push(&OtherSushi{pri: memo[i][j], kind: i})
		}
	}

	num := tops.Len()
	ans := 0
	if num >= k {
		// k個になるまで小さいものから捨てる
		for i := 0; i < num-k; i++ {
			tops.pop()
			// t := tops.pop()
			// PrintfDebug("tops throwed: pri: %d, kind: %d\n", t.pri, t.kind)
		}
	} else {
		// k個になるまでothersから大きいものを追加する
		for i := 0; i < k-num; i++ {
			o := others.pop()
			ans += o.pri
			// PrintfDebug("others added: pri: %d, kind: %d\n", o.pri, o.kind)
		}
	}

	// 変化がなくなるまでtopのものを捨てて、othersのものを採用する
	for {
		if others.Len() == 0 {
			break
		}

		cx := tops.Len()
		t := tops.pop()
		o := others.pop()
		diff := (2*cx - 1) + t.pri
		if diff < o.pri {
			ans += o.pri
		} else {
			tops.push(t)
			break
		}
	}

	// topsのものを勘定する
	x := tops.Len()
	ans += x * x
	for tops.Len() > 0 {
		ans += tops.pop().pri
	}
	fmt.Println(ans)
}

type TopSushi struct {
	pri  int
	kind int
}
type TopSushiPQ []*TopSushi

// Interfaces
func NewTopSushiPQ() *TopSushiPQ {
	temp := make(TopSushiPQ, 0)
	pq := &temp
	heap.Init(pq)

	return pq
}
func (pq *TopSushiPQ) push(target *TopSushi) {
	heap.Push(pq, target)
}
func (pq *TopSushiPQ) pop() *TopSushi {
	return heap.Pop(pq).(*TopSushi)
}

func (pq TopSushiPQ) Len() int           { return len(pq) }
func (pq TopSushiPQ) Less(i, j int) bool { return pq[i].pri < pq[j].pri } // <: ASC, >: DESC
func (pq TopSushiPQ) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}
func (pq *TopSushiPQ) Push(x interface{}) {
	item := x.(*TopSushi)
	*pq = append(*pq, item)
}
func (pq *TopSushiPQ) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

type OtherSushi struct {
	pri  int
	kind int
}
type OtherSushiPQ []*OtherSushi

// Interfaces
func NewOtherSushiPQ() *OtherSushiPQ {
	temp := make(OtherSushiPQ, 0)
	pq := &temp
	heap.Init(pq)

	return pq
}
func (pq *OtherSushiPQ) push(target *OtherSushi) {
	heap.Push(pq, target)
}
func (pq *OtherSushiPQ) pop() *OtherSushi {
	return heap.Pop(pq).(*OtherSushi)
}

func (pq OtherSushiPQ) Len() int           { return len(pq) }
func (pq OtherSushiPQ) Less(i, j int) bool { return pq[i].pri > pq[j].pri } // <: ASC, >: DESC
func (pq OtherSushiPQ) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}
func (pq *OtherSushiPQ) Push(x interface{}) {
	item := x.(*OtherSushi)
	*pq = append(*pq, item)
}
func (pq *OtherSushiPQ) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

/*******************************************************************/

/*********** I/O ***********/

var (
	// ReadString returns a WORD string.
	ReadString func() string
	stdout     *bufio.Writer
)

func newReadString(ior io.Reader, sf bufio.SplitFunc) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+9)) // for Codeforces
	r.Split(sf)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

// ReadInt returns an integer.
func ReadInt() int {
	return int(readInt64())
}
func ReadInt2() (int, int) {
	return int(readInt64()), int(readInt64())
}
func ReadInt3() (int, int, int) {
	return int(readInt64()), int(readInt64()), int(readInt64())
}
func ReadInt4() (int, int, int, int) {
	return int(readInt64()), int(readInt64()), int(readInt64()), int(readInt64())
}

// ReadInt64 returns as integer as int64.
func ReadInt64() int64 {
	return readInt64()
}
func ReadInt64_2() (int64, int64) {
	return readInt64(), readInt64()
}
func ReadInt64_3() (int64, int64, int64) {
	return readInt64(), readInt64(), readInt64()
}
func ReadInt64_4() (int64, int64, int64, int64) {
	return readInt64(), readInt64(), readInt64(), readInt64()
}

func readInt64() int64 {
	i, err := strconv.ParseInt(ReadString(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

// ReadIntSlice returns an integer slice that has n integers.
func ReadIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = ReadInt()
	}
	return b
}

// ReadInt64Slice returns as int64 slice that has n integers.
func ReadInt64Slice(n int) []int64 {
	b := make([]int64, n)
	for i := 0; i < n; i++ {
		b[i] = ReadInt64()
	}
	return b
}

// ReadFloat64 returns an float64.
func ReadFloat64() float64 {
	return float64(readFloat64())
}

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

// ReadFloatSlice returns an float64 slice that has n float64.
func ReadFloat64Slice(n int) []float64 {
	b := make([]float64, n)
	for i := 0; i < n; i++ {
		b[i] = ReadFloat64()
	}
	return b
}

// ReadRuneSlice returns a rune slice.
func ReadRuneSlice() []rune {
	return []rune(ReadString())
}

/*********** Debugging ***********/

// ZeroPaddingRuneSlice returns binary expressions of integer n with zero padding.
// For debugging use.
func ZeroPaddingRuneSlice(n, digitsNum int) []rune {
	sn := fmt.Sprintf("%b", n)

	residualLength := digitsNum - len(sn)
	if residualLength <= 0 {
		return []rune(sn)
	}

	zeros := make([]rune, residualLength)
	for i := 0; i < len(zeros); i++ {
		zeros[i] = '0'
	}

	res := []rune{}
	res = append(res, zeros...)
	res = append(res, []rune(sn)...)

	return res
}

// Strtoi is a wrapper of strconv.Atoi().
// If strconv.Atoi() returns an error, Strtoi calls panic.
func Strtoi(s string) int {
	if i, err := strconv.Atoi(s); err != nil {
		panic(errors.New("[argument error]: Strtoi only accepts integer string"))
	} else {
		return i
	}
}

// PrintIntsLine returns integers string delimited by a space.
func PrintIntsLine(A ...int) string {
	res := []rune{}

	for i := 0; i < len(A); i++ {
		str := strconv.Itoa(A[i])
		res = append(res, []rune(str)...)

		if i != len(A)-1 {
			res = append(res, ' ')
		}
	}

	return string(res)
}

// PrintIntsLine returns integers string delimited by a space.
func PrintInts64Line(A ...int64) string {
	res := []rune{}

	for i := 0; i < len(A); i++ {
		str := strconv.FormatInt(A[i], 10) // 64bit int version
		res = append(res, []rune(str)...)

		if i != len(A)-1 {
			res = append(res, ' ')
		}
	}

	return string(res)
}

// PrintfDebug is wrapper of fmt.Fprintf(os.Stderr, format, a...)
func PrintfDebug(format string, a ...interface{}) {
	fmt.Fprintf(os.Stderr, format, a...)
}

// PrintfBufStdout is function for output strings to buffered os.Stdout.
// You may have to call stdout.Flush() finally.
func PrintfBufStdout(format string, a ...interface{}) {
	fmt.Fprintf(stdout, format, a...)
}


Measured memory_bytes: 12160