#!/usr/local/bin/perl
# Jaime Prilusky, 2009

  my $num = $ARGV[0];
  print "position $num: ",fibo($num),"\n";

sub fibo {
  my($n) = @_;
  return 0 if ($n == 0);
  return 0 if ($n == 1);
  return 1 if ($n == 2);
  $f{$n-1} = fibo($n-1) if (!$f{$n-1});
  $f{$n-2} = fibo($n-2) if (!$f{$n-2});
  return $f{$n-1} + $f{$n-2};
}