Given an array of integers and a positive integer , determine the number of pairs where and + is divisible by .
Example
 
   
Three pairs meet the criteria: and .
Function Description
Complete the divisibleSumPairs function in the editor below.
divisibleSumPairs has the following parameter(s):
- int n: the length of array
- int ar[n]: an array of integers
- int k: the integer divisor
Returns 
-   int: the number of pairs  
Input Format
The first line contains  space-separated integers,  and . 
The second line contains  space-separated integers, each a value of .  
Constraints
Sample Input
STDIN           Function
-----           --------
6 3             n = 6, k = 3
1 3 2 6 1 2     ar = [1, 3, 2, 6, 1, 2]
Sample Output
 5
Explanation
Here are the valid pairs when :