Excel: SUM values in a column if matching data in multiple other columns

Hello,

I would like to sum data in column L (genetic marker length) if the following conditions are met

1. Matching value in column D (sample ID)

and

2. Matching value in column K (genetic marker)

Column D contains a wide variety of numeric sample/subject IDs and column K contains a variety of genetic markers. Column L is the length of those markers. Essentially I want excel to add the lengths for all identical markers for each sample ID. Extra bonus if I can also display the value in column L when those criteria are not met, so my data is still all in a single column.

I attached an abbreviated file containing mock data in my columns of interest for this question.