#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
using namespace std;
#define ll long long
#define INF  0x7FFFFFFF
const int N = 1e7+10;
const int M = N*4;
ll a[N];
//桶排
ll record[N];   //下标: 数组元素 value: 该元素出现的个数  
int main() {
//    ios::sync_with_stdio(false); cin.tie(0);
	int n, m;
	scanf("%d%d",&n,&m);
	ll res = 0;
	for(int i = 1; i <= n; ++i) {
		scanf("%lld",&a[i]);
		record[a[i]]++;
		a[i] -= m; 
	}
	for(int i = 1; i <= n; ++i) {
		res += record[a[i]];
	} 
	printf("%lld",res);
    return 0;
}