my %m=(Jan=>1, Feb=>2, Mar=>3, Apr=>4,  May=>5,  Jun=>6,
       Jul=>7, Aug=>8, Sep=>9, Oct=>10, Nov=>11, Dec=>12);
sub datesort
{ return $a->[3] <=> $b->[3] || $m{$a->[2]} <=> $m{$b->[2]} || $a->[1] <=> $b->[1]; }

my @list=map{$_=$_->[0]}sort{datesort()}map{$_=[$_,(split(/\//,$_))]}keys(%days);