Divisible Pairs Sum: Hackerearth problem and solution in java

Divisible Pairs Sum: Hackerearth problem

You are given an array of  integers, , and a positive integer, . Find and print the number of  pairs where  and  +  is evenly divisible by .

Input Format

The first line contains  space-separated integers,  and , respectively. 
The second line contains  space-separated integers describing the respective values of .

Constraints

Output Format

Print the number of  pairs where  and  +  is evenly divisible by .

Sample Input

6 3
1 3 2 6 1 2

Sample Output

 5

Solution in java:

import java.io.*;

import java.util.*;

import java.text.*;

import java.math.*;

import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);

        int n = in.nextInt();

        int k = in.nextInt();

        int a[] = new int[n];

        for(int a_i=0; a_i < n; a_i++){

            a[a_i] = in.nextInt();

        }

        int count=0;

        for(int i =0;i<n;i++){

            for(int j=i+1;j<n;j++){

              if((a[i]+a[j])%k==0)

                  count++;

              

            }

        }

        System.out.println(count);

    }

}