import java.io.PrintWriter
import scala.collection.mutable.*
import scala.io.StdIn.*
import scala.util.chaining.*
import scala.math.*
import scala.reflect.ClassTag
import scala.util.*
import scala.annotation.tailrec
import scala.collection.mutable


@main def main() =
  val Array(n, m) = readLine().split(' ').map(_.toInt)
  val jewels = Array.fill(n){
    val Array(v, w) = readLine().split(' ').map(_.toInt)
    v -> w
  }
  val memo = Array.fill(m + 1){0L}
  var result = 0L
  for (v, w) <- jewels.sortBy(_._1)(Ordering[Int].reverse) do
    for i <- m to w by -1 do
      memo(i) = max(memo(i), memo(i - w) + v)
    result = max(result, v * memo.last)
  println(result)