#include <unordered_map>
#include <vector> 
#include <iostream>
//用 hash + map 的原因是不希望遍历 O(n^2) 
using namespace std;
int main(){
	unordered_map<long long, int> s;
	vector<long long> arr;
	long long n, m;
	cin >> n >> m;
	long long tmp;
	for(int i = 0; i < n; i++){
		cin >> tmp;
		arr.push_back(tmp);
		s[tmp]++; 
	}
	long long need;
	long long js = 0;
	for(int i = 0; i < n; i++){
		need = arr[i] - m;
		if(s.count(need)) js += s[need];//s[need]的值是 pair.seconds 
		//s.emplace(make_pair(arr[i], 1));//不行，如果arr[i]存在，会直接放弃插入 
	}
	cout << js << endl;
	return 0;
}