program yukicoder_3
  use, intrinsic :: iso_fortran_env
  implicit none
  integer(int32), parameter :: infini = ishft(1, 28)
  integer(int32) :: n
  integer(int32), allocatable :: dp(:)
  read(input_unit, *) n
  allocate(dp(n), source = infini)
  dp(1) = 1_int32
  call dfs(1)
  write(output_unit, '(i0)') merge(dp(n), -1, dp(n) /= infini)
contains
  recursive subroutine dfs(v)
    integer(int32), intent(in) :: v
    integer(int32) :: diff, nv
    integer(int32), parameter :: factor(1:2) = [1, -1]
    integer(int32) :: i
    diff = popcnt(v)
    do i = 1, size(factor)
       nv = v + factor(i)*diff
       if (nv < 1 .or. nv > n) cycle
       if (dp(v) + 1 >= dp(nv)) cycle
       dp(nv) = dp(v) + 1
       call dfs(nv)
    end do
  end subroutine dfs
end program yukicoder_3