#!/usr/local/bin/perl
# Jaime Prilusky, 2003
use Benchmark;

  $t0 = new Benchmark;

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

  $t1 = new Benchmark;
  $td = timediff($t1, $t0);
  print "the code took:",timestr($td),"\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};
}