package main

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

var sc = bufio.NewScanner(os.Stdin)
var wr = bufio.NewWriter(os.Stdout)

func print(x ...interface{}) {
	fmt.Fprintln(wr, x...)
}

func slice_conv(x []int, sep string) string {
	ret := make([]string, len(x))
	for i, v := range x {
		ret[i] = strconv.Itoa(v)
	}
	return strings.Trim(strings.Join(ret, sep), "[]")
}

func nextString() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return i
}

func i2() (int, int) {
	return nextInt(), nextInt()
}

func nextFloat() float64 {
	sc.Scan()
	i, err := strconv.ParseFloat(sc.Text(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

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

func nmax(a ...int) int {
	ret := a[0]
	for _, e := range a {
		ret = max(ret, e)
	}
	return ret
}

func nmin(a ...int) int {
	ret := a[0]
	for _, e := range a {
		ret = min(ret, e)
	}
	return ret
}

func abs(a int) int {
	return int(math.Abs(float64(a)))
}

const (
	MOD = 1000000007
	INF = 1 << 10
	M   = 100
)

func modAdd(a *int, b int) {
	*a += b
	if *a >= MOD {
		*a -= MOD
	}
}

func chmax(a *int, b int) {
	if *a < b {
		*a = b
	}
}

type Pair struct {
	v, w int
}

func main() {
	defer wr.Flush()
	sc.Split(bufio.ScanWords)

	n, m := i2()

	items := make([]Pair, n)
	for range items {
		v, w := i2()
		items = append(items, Pair{v, w})
	}
	sort.Slice(items, func(i, j int) bool {
		return items[i].v > items[j].v
	})

	dp := make([]int, m+1)
	ans := 0

	for _, p := range items {
		for i := m; i >= p.w; i-- {
			chmax(&dp[i], dp[i-p.w]+p.v)
		}
		chmax(&ans, dp[m]*p.v)
	}
	print(ans)
}