Finite p-groups whose proper subgroups are of class ≤ n

A finite group G is said to be a minimal non-𝒫n group if G itself is not a group of nilpotency class ≤ n and all of whose proper subgroups are of nilpotency class ≤ n. In this paper, we get a upper bound of nilpotency class of a minimal non-𝒫n p-group and some properties about minimal non-𝒫2 p-groups.