#!/usr/bin/env perl
# Copyright 2005 Daniel Cer (daniel.cer@cs.colorado.edu)
#
# This work is licensed under the Creative Commons Attribution-NonCommercial-
# ShareAlike License. To view a copy of this license, visit 
# http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to 
# Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 
# 94105, USA.

sub fibonacci ($) {
  my $n = shift;
  return -1 if ($n <= 0); return 1 if ($n <= 2);
  return fibonacci($n-1) + fibonacci($n-2);
}

if ($#ARGV != 0) {
   print stderr "Usage:\n\t$0 (n-th fibonacci # to calculate)\n";
   exit -1;
}

print "fibonacci($ARGV[0]): ".fibonacci($ARGV[0])."\n";