subroutine get_prime(isPrime, N)
  implicit none
  integer::i,j,N
  integer,parameter::prime=1,nonprime=0
  integer,allocatable::isPrime(:)

  isPrime=prime
  isPrime(1)=nonprime

  do i=2, FLOOR(SQRT(REAL(N)))
     if(isPrime(i).eq.prime) then
        do j=i+i, N, i
           isPrime(j) = nonprime
        end do
     end if
  end do

end subroutine get_prime

program main
  interface
     subroutine get_prime(isPrime, N)
       integer::N
       integer,allocatable::isPrime(:)
     end subroutine get_prime
  end interface
  integer::primelimit
  integer*8::total
  integer,allocatable::isPrime(:)

  read *, N,L

  primelimit = L/(N-1)

  if(primelimit.lt.2) then
     print '(i0)', 0
     return
  end if

  allocate(isPrime(primelimit))
  call get_prime(isPrime, primelimit)

  total = 0
  do i=1, primelimit
     if(isPrime(i).eq.0) cycle
     total = total + (L-(N-1)*i) + 1
  end do

  print '(i0)', total

end program