Kata

Sexy primes are pairs of two primes that are 6 apart. In this kata, your job is to complete the function which returns true if x & y are sexy, false otherwise.

Examples

5, 11   -->  true
61, 67  -->  true
7, 13   -->  true
5, 7    -->  false
1, 7    -->  false  (1 is not a prime)

Note: x & y are always positive integers, but they are not always in order of precendence... For example you can be given either (5, 11) or (11, 5) - both are valid.