#!/usr/bin/perl -w
use strict;
$|++;

use Time::Local;

my $online = [
              map { timelocal( (split /[:\/\s]+/)[2,1,0,4,3,5] ) } <DATA>
             ];

my $total = 0;

for ( local $_ = 0; $_ <= $#{$online}; $_ += 2 ) {
  $total += $online->[$_+1] - $online->[$_];
}

print "$total seconds online\n"

__DATA__
10:09:55        05/28/00        Sunday
10:37:45        05/28/00        Sunday
09:27:02        05/29/00        Monday
09:34:05        05/29/00        Monday
20:48:00        05/29/00        Monday
20:57:19        05/29/00        Monday
21:38:32        05/29/00        Monday
21:40:14        05/29/00        Monday
09:32:50        05/30/00        Tuesday
09:37:29        05/30/00        Tuesday
13:03:23        05/30/00        Tuesday
13:09:45        05/30/00        Tuesday