#include <bits/stdc++.h>
using namespace std;

int main() {
	int n,target;
	cin>>n>>target;
	
	vector<int> numbers(n);
	
	for(auto& number: numbers){
		cin>>number;
	}
	
	int answer = 0;
	
	unordered_map<int,int> freq;
	
	for(int i=0; i<n; i++){
		
		
		int reqNum1 = target + numbers[i];
		int reqNum2 = numbers[i] - target;
		
		if(freq.find(reqNum1) != freq.end())answer += freq[reqNum1];
		if(freq.find(reqNum2) != freq.end())answer += freq[reqNum2];
		
		freq[numbers[i]]++;
	}
	
	cout<<answer;
	
	return 0;
}