I don’t know what your intention is with this question but assuming the confusion with the word management in both names. IIM Rohtak and IHM are two different institutions serving/catering to different industries and different academic focuses.
IIM Rohtak stands for Indian Institute of Management situated in Rohtak which is a B-school offering post-graduate management programs such as MBA, executive MBA, and Ph.D. IIM Rohtak trains future corporate leaders in business and management. Admission is tough and based on merit and national entrance tests.
On the other hand, IHM stands for Institute of Hotel Management offering undergraduate and postgraduate programs in hotel management and hospitality, IHM teaches food production, housekeeping, front office operations, and food and beverage service.
Ultimately it is like comparing apples with oranges. Hope I answered your query.