use DateTime::Format::DateParse;

my $p1 = shift;
my $p2 = shift;

my $first_dt = DateTime::Format::DateParse->parse_datetime("$p1");
my $second_dt = DateTime::Format::DateParse->parse_datetime("$p2");

my $first_dt_syd = $first_dt->set_time_zone('Australia/Sydney');
my $second_dt_syd = $second_dt->set_time_zone('Australia/Sydney');

my $diff =  $first_dt_syd->delta_days( $second_dt_syd )->delta_days;