GDG versions in a JCL

There is a JCL which has three steps.

Step 1:

It uses the GDG(0) as input and creates another GDG version.

INPUT – GDG(0)
OUTPUT- GDG version created by step 1

Step 2:

It uses GDG(0) and the output of step 1 as input and creates another GDG version.

INPUT  РGDG(0) and Output GDG version created by step 1
OUTPUT – GDG version created by step 2

Step 3:

It uses the GDG output created by Step 1 and step 2 as input and creates another GDG version.

INPUT  РGDG version created by step 1 and Step 2
OUTPUT – GDG version created by step 3

First question:

What are the version numbers used and created by each step?

“; ; ; ;

Second Question:

If JCL abends after successful execution of Step 2, and needs to be restarted from Step 3, are there
any changes required in the GDG version numbers used in Step 3.