use Date::Manip;
    my $total = ParseDateDelta("");

    while (<>) {
        chomp;
        my $start = $_;
        chomp(my $end = <>);

        ## Build date/time stamps for start and end.
        $start = join ' ', (split /\t/, $start)[1,0];
        $end   = join ' ', (split /\t/, $end)[1,0];

        ## Add delta of start and end stamps to
        ## total delta.
        $total = DateCalc( DateCalc($start, $end), $total);
    }

    print "Total hours online: ",
        Delta_Format($total, 0, "%hd"), "\n";