import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class DivisiblePairsSum {

    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];
        int counter=0;
        for(int a_i=0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        for (int i=0;i<n-1;i++) {
            for (int j=i+1;j<n;j++) {
                if ((a[i]+a[j])%k==0) counter++;
            }
        }
        System.out.println(counter);
    }
}

Create DivisiblePairsSum.java