program main
   integer(8) N, K, i
   integer(8), allocatable :: a(:), b(:)
   read(*, *) N, K
   allocate(a(1: N))
   allocate(b(1: N))
   do i = 1, N
       read(*, *) a(i), b(i)
   end do
   call heapsort(N,a)
   call heapsort(N,b)
   do i = 1, N
       if(1 <= K .and. K <= b(i)) then
	       write(*, *) a(i)
	       exit
	   else
	       K = K - b(i)
	   end if
   end do
end program main


subroutine heapsort(n,array)
  implicit none
  integer(8),intent(in) :: n
  integer(8),intent(inout) :: array(1:n)
  
  integer(8) ::i,k,j,l
  integer(8) :: t
  
  if(n.le.0)then
     write(6,*)"Error, at heapsort"; stop
  endif
  if(n.eq.1)return

  l=n/2+1
  k=n
  do while(k.ne.1)
     if(l.gt.1)then
        l=l-1
        t=array(L)
     else
        t=array(k)
        array(k)=array(1)
        k=k-1
        if(k.eq.1) then
           array(1)=t
           exit
        endif
     endif
     i=l
     j=l+l
     do while(j.le.k)
        if(j.lt.k)then
           if(array(j).lt.array(j+1))j=j+1
        endif
        if (t.lt.array(j))then
           array(i)=array(j)
           i=j
           j=j+j
        else
           j=k+1
        endif
     enddo
     array(i)=t
  enddo

  return
end subroutine heapsort