Suppose $n$ processors are connected in a linear array as shown below. Each processor has a number. The processors need to exchange numbers so that the numbers eventually appear in ascending order (the processor $\rm P1$ should have the minimum value and the the processor $\rm Pn$ should have the maximum value).

The algorithm to be employed is the following. Odd numbered processors and even numbered processors are activated alternate steps; assume that in the first step all the even numbered processors are activated. When a processor is activated, the number it holds is compared with the number held by its right-hand neighbour (if one exists) and the smaller of the two numbers is retained by the activated processor and the bigger stored in its right hand neighbour.
How long does it take for the processors to sort the values?

They are asking for steps here not time complexity. In each step even/odd processors are doing constant work i.e they are activated simulatenously and swapping is done.

Exact N step take take worst case decresing oder . 1st elemnt come to its coreect place at n th step at the same time all elemnt goes to its coreect place.