#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main(){
	ll n,c,sum=0;
	cin>>n>>c;
	ll a[n],t[100000005];
	for(ll i=0;i<n;i++){
		cin>>a[i];
		t[a[i]]++;
	}
	for(ll i=0;i<n;i++){
		if(a[i]<c){
			continue;
		}
		sum+=t[a[i]-c];
	}
	cout<<sum<<endl;
	return 0;
}

#4RE 其他AC