Create Hierarchical Tree from 2 Columns in SQL

I am having a large set of data in 2 columns where I need to create hierarchical structure from it. Below is the input table structure.

Requirement is to find all the Child of Parent. But the issue here is Parent can also be a child of another Parent in the same column.

I was trying with below query and nowhere near to creating a hierarchical structure. Query tried:

with cteP as (
     select  Parent,Child
     from [dbo].[Data]  
     where Parent is not null
      Union  All
      Select r.Parent,r.Child
      From   [dbo].[Data] r
      inner join cteP on  r.Parent  = cteP.Parent
Select *
  From cteP A
--Order By A.Parent
 option (maxrecursion 0)

I tried using hierarchy id and getting the error "Implicit conversion from data type hierarchyid to varchar is not allowed. Use the CONVERT function to run this query."

I want my output table in below format until the child is null: