my $digs= 3;
    my $fact= 1;
    $fact *= $_   for  2..$digs;

    my %h;
    my $getDigits= nestedLoops( [
        [0..9],
        ##[1..9],
        ( sub { [ $_[-1] .. 9 ] } ) x ($digs-1),
        ##( sub { [ $_[-1]+1 .. 9 ] } ) x ($digs-1),
    ] );
    my @list;
    while(  @list= $getDigits->()  ) {
        my @p;
        do {
            push @p, join "", @list;
        } while(  nextPermute( @list )  );
        nestedLoops(
            [
                [0..$#p],
                ( sub { [ $_[-1]+1 .. $#p ] } ) x ($fact-1),
            ],
            {
                OnlyWhen => 1,
                Code => sub {
                    my $expr= join "+", @p[@_];
                    my $noOct= $expr;
                    $noOct =~ s/(?<!\d)0+(\d)/$1/g;
                    ## $expr= "()"   if  @_ < 6;
                    $h{eval $noOct} .= "=$expr";
                },
            },
        );
    }

    ##for my $k ( sort { length($h{$a}) <=> length($h{$b})
    ##    || $a <=> $b } keys %h ) {
    for my $k ( sort { $a <=> $b } keys %h ) {
        print "$k$h{$k}\n"
            if  1990 < $k and $k < 2010;
            ##if  $h{$k} =~ /\d/  &&  index($h{$k},"()") < 0;
    }