// 计数排序 + 遍历 O(n+A) 
#include <bits/stdc++.h>
using namespace std;
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
#define PII pair<int,int>
const int N = 1e7+10,M = 2e7+10;
int n,C;
int num[M]; 

int rd()
{
    int x = 0; int f = 1; char c = getchar();
    for (; !isdigit(c); c = getchar()) if (c == '-') f = - 1;
    for (; isdigit(c); c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
    return x *= f;
}

signed main()
{
//  freopen("input.in","r",stdin); 
    
    cin>>n>>C;
    F(i,1,n)
    {
        int x;x=rd();
        num[x]++; 
    }
    int sum = 0;
    F(B,1,20000000 - C)
    {
        int A = B + C;
        sum += num[A] * num[B]; 
    }
    cout<<sum;
    return 0;
}