use DateTime;
my $dt = DateTime->now->truncate(to=>'month');
for (1..24) {
	my $last = $dt->clone->add(months=>1)->subtract(days=>1);
	print $dt->ymd," to ",$last->ymd,"\n";
	$dt->subtract(months=>1);
}
__END__
2017-06-01 to 2017-06-30
2017-05-01 to 2017-05-31
2017-04-01 to 2017-04-30
... etc.