use Data::Dump qw/ dd /;
## this?
{
    my( %RedText, %DerText );
    $RedText{'Entry 1'}{D}=1;
    $RedText{'Entry 1'}{N}=2;

    $DerText{'Entry 3'}{N}=6;
    $DerText{'Entry 3'}{""}=7; ## uh oh, something fishy
    
    $DerText{'Entry 5'}{D}=4; ## uh oh, duplicates overwrite, no good
    $DerText{'Entry 5'}{D}=9;
    
    dd( \%RedText, \%DerText );
}

## maybe this?
{
    my( %RedText, %DerText );
    
    $RedText{'Entry 1'}{1}='D';
    $RedText{'Entry 1'}{2}='N';

    $DerText{'Entry 3'}{6}='N';
    $DerText{'Entry 3'}{7}='';
    
    $DerText{'Entry 5'}{4}='D';
    $DerText{'Entry 5'}{9}='D';
    
    dd( \%RedText, \%DerText );
}