#include <bits/stdc++.h>
using namespace std;
long long n,c,a[(1<<30)+1]，ai,ans;
int main (){
	cin >> n >> c;
	for (int i=1;i<=n;i++){
		scanf("%d",&ai);
		a[ai]++;
	}  //输入
	for (int i=0;i<=c/2;i++){ //i即题中的A
		if(a[i]!=0&&a[i-c]!=0) ans+=a[i]*a[c-i]; 
	}//计算ans的值
	cout << ans; //输出
	return 0;
}