#!/usr/bin/perl

use strict;
use warnings;

use Date::Manip;

my $now = ParseDate 'now';
my $then = ParseDate 'next month';
substr($then,6,2) = 21;
my $delta = DateCalc $now, $then;
my $seconds = Delta_Format $delta, 0, '%sh';
print "seconds=$seconds days=", $seconds/(60*60*24), "\n";