import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        Map<Integer,Integer>map = new HashMap<>();
        int n = scan.nextInt();
        int c = scan.nextInt();
        int[] arr = new int[n];
        for(int i = 0;i<n;i++){
            arr[i] = scan.nextInt();
            map.put(arr[i], map.getOrDefault(arr[i], 0)+1);
        }
        int ans = 0;
        for(int i = 0;i < n;i++){
            int b = arr[i] - c;
            ans += map.getOrDefault(b, 0);
        }
        System.out.println(ans);
    }
}