Školjka Let 
be a set of 
different prime numbers and 
a set of 
different composite numbers each of which is a product of two (not necessarily different) numbers from . The set is divided into disjoint four-element subsets such that each of the numbers in one set has a common prime divisor with at least two other numbers in that set. How many such partitions of are there ?
be a set of different prime numbers and a set of different composite numbers each of which is a product of two (not necessarily different) numbers from . The set is divided into disjoint four-element subsets such that each of the numbers in one set has a common prime divisor with at least two other numbers in that set. How many such partitions of are there ?