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

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