Standard input is empty

ans =  3
ans =  3
----------------------------------------------------------------------
GNU Octave Version: 4.0.0
GNU Octave License: GNU General Public License
Operating System: Linux 2.6.34 #6 SMP Fri Jan 21 15:21:52 CET 2011 i686
----------------------------------------------------------------------
Package Name  | Version | Installation directory
--------------+---------+-----------------------
econometrics *|   1.1.1 | /usr/share/octave/packages/econometrics-1.1.1
       image  |   2.4.1 | /usr/share/octave/packages/image-2.4.1
          io  |  2.2.11 | /usr/share/octave/packages/io-2.2.11
       optim *|   1.4.1 | /usr/share/octave/packages/optim-1.4.1
      struct *|  1.0.11 | /usr/share/octave/packages/struct-1.0.11