#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
inline int power(int a, int b) {
    int x = 1;
    while (b) {
        if (b & 1) x *= a;
        a *= a;
        b >>= 1;
    }
    return x;
}


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

//_ ***************************** START Below *******************************



vector<int> a;
int consistency(int n, int k) {
	
	unordered_map<int,int> mp;
	int ans = 0;
	for(int i=0; i<n; i++){
		if(mp.count(a[i] - k)){
			ans += mp[a[i]-k];
		}
		if(k!=0 && mp.count(a[i] + k)){
			ans += mp[a[i]+k];
		}
		mp[a[i]]++;
	}
	
	return ans;
}

















int practice(int n, int k) {
	
	int ans = 0;
	

	
	return ans;
	
}



void solve() {
    
    int n, k;
    cin >> n >> k;
    a.resize(n);
    for(int i=0; i<n; i++) cin >> a[i];
    
    cout << consistency(n, k) <<  endl ;
    
    
    // cout << consistency(n, k) << " -> " << practice(n, k) << endl ;

}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    while (t--) {
        solve();
    }

    return 0;
}