Prime Distance
[ASSIGNMENT]:
      The Sum Of Prime Distance
We define the Prime Distance between 
two even numbers as: The number of 
primes between two even numbers! 

The Prime Distance between 16 and 20 is 2, 
because there are two primes between 
 16 and 20 --> (17,19).

 TASK: Given an integer array arr.
Calculate the sum of the Prime Distance 
of each pair of elements in the array?

 NOTE!
All elements in the array are unique even 
numbers and they are arranged in ascending 
order.


 #Example 1.
 
For arr = [ 4,6,12 ],
    the output should be 6.

   prime distance of (4, 6) --> 1
   prime distance of (6,12) --> 2
   prime distance of (4,12) --> 3 
 
    --> 1+2+3 = 6 

 #Example 2.
 
 arr = [ 4,6,12,14,16,20 ],
    the output should be 40.

   prime distance of ( 4, 6) --> 1 
   prime distance of ( 6,12) --> 2 
   prime distance of (12,14) --> 1
   prime distance of (14,16) --> 0
   prime distance of (16,20) --> 2
 
   prime distance of ( 4,12) --> 3
   prime distance of ( 6,14) --> 3
   prime distance of (12,16) --> 1
   prime distance of (14,20) --> 2
 
   prime distance of ( 4,14) --> 4
   prime distance of ( 6,16) --> 3
   prime distance of (12,20) --> 3
 
   prime distance of (4,16) --> 4
   prime distance of (6,20) --> 5 
 
   prime distance of (4,20) --> 6

    --> 1+2+1+0+2+3+3+1+2+4+3+3+4+5+6 = 40 
     

  HappyCodings! by @boolean maybe
Prime Distance [TASK]
