program main
  implicit none
  integer::N,D,M
  integer::i,cur,total,step,next
  integer,allocatable::ashiba(:)
  read *,N,D
  allocate(ashiba(0:D))
  cur = 0
  ashiba=1
  total = 0
  M = D-(N-N/D*D)

  do i=1,D
     ashiba(cur) =0
     next = MOD(cur + M,D)
     step = (N + next - cur)/D
     total = total + step
     if(ashiba(next).eq.0) then
        total = total -1
        exit
     end if
     cur = next
  end do

  print '(i0)',total
end program main