use Date::Manip;
use strict;

my $mode = 2; # 2 = business mode, 1 = normal mode

my $dateA = ParseDate("today at 1PM");
my $dateB = ParseDate("tomorrow at $ARGV[0]");
my $err;
my $difference = Delta_Format(DateCalc($dateA,$dateB,\$err,$mode),0,"%hh");

print "$difference hours.\n";