Return final numbers of days next to final date value DAX

[TornDigorn]

Hello dear PBI community

I need help in creating a DAX expression that will allow me to return the value "number of days" in the column "return final number of days" but only in the row where the date appears in the "final date" column,  other rows should be blank. 

Expected result below -  (Expected returned value in green)

[lbendlin]

Please provide sample data (with sensitive information removed) that covers your issue or question completely, in a usable format (not as a screenshot).
https://community.fabric.microsoft.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-...
Please show the expected outcome based on the sample data you provided.

https://community.fabric.microsoft.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447...