package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
	return scanner
}
func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextUint64(scanner *bufio.Scanner) uint64 {
	i, _ := strconv.ParseUint(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	cnt := 0
	if os.Getenv("MASPY") == "ますピ" {
		fp, _ = os.Open(os.Getenv("BEET_THE_HARMONY_OF_PERFECT"))
		cnt = 2
	}
	if os.Getenv("MASPYPY") == "ますピッピ" {
		wfp, _ = os.Create(os.Getenv("NGTKANA_IS_GENIUS10"))
	}
	scanner := getScanner(fp)
	writer := bufio.NewWriter(wfp)
	solve(scanner, writer)
	for i := 0; i < cnt; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
	writer.Flush()
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	k := getNextInt(scanner)
	pp := make([]pizza, n)
	for i := 0; i < n; i++ {
		pp[i].p = getNextInt(scanner)
		pp[i].d = getNextInt(scanner)
	}
	sort.SliceStable(pp, func(i, j int) bool {
		return pp[i].p > pp[j].p
	})
	dp := make([][2]cint, k+1)
	for i := 0; i < k+1; i++ {
		dp[i][1] = -1
	}
	for i := 0; i < n; i++ {
		for j := k; j >= 0; j-- {
			if dp[j][1] != -1 {
				dp[j][0].max(dp[j][1] + cint(pp[i].d))
			}
			if j-pp[i].p >= 0 {
				dp[j][1].max(dp[j-pp[i].p][0] + cint(pp[i].d))
			}
		}
	}
	fmt.Fprintln(writer, *dp[k][0].max(dp[k][1]))
}

type pizza struct {
	p, d int
}

type cint int

func (x *cint) min(y cint) *cint {
	if *x > y {
		*x = y
	}
	return x
}
func (x *cint) max(y cint) *cint {
	if *x < y {
		*x = y
	}
	return x
}