my @files= <*>;
@files= do {
    my @mo= ( qw(Jan Feb Mar Apr May Jun
        Jul Aug Sep Oct Nov Dec), 'a'..'l' );
    my %mo; @mo{@mo}= reverse @mo;
    grep {
        s/^(.)/$mo{$1}/
    } sort grep {
        s/^(...)/$mo{$1}/
    } @files;
};