#include <set>
#include <iostream>
using namespace std;
int main(){
	multiset<int> s;
	int n, m;
	cin >> n >> m;
	int tmp;
	for(int i = 0; i < n; i++){
		cin >> tmp;
		s.emplace(tmp);
	}
	int js = 0;
	for(auto it = s.begin(); it != s.end(); it++){
		js += s.count(*it - m);
	} 
	cout << js << endl;
	return 0;
}