Write recursive t-sql code to generate reverse of given string

Create Function [dbo].[fn_Reverse](@v_Input nvarchar(max))
Returns nvarchar(max)
as
Begin
If (len(@v_Input) <> 1)
Begin
return [dbo].[fn_Reverse](substring(@v_Input, 2, len(@v_Input) - 1)) + substring(@v_Input, 1, 1)
End
return @v_Input
End
GO

select [dbo].[fn_Reverse]('acbdkkdfkdkf')
Go

--> fkdkfdkkdbca