#include <stdio.h>
#include <stdlib.h> 
#define MAX 100000

int cmp_ll(const void *a, const void *b){
	int  x = *(int *)a; 
	int  y = *(int *)b; 
	
	if(x < y) return -1; 
	if(x > y) return 1; 
	return 0; 
} 

int find( int N, int target, int *uniq){
	int left= 0;
	int right = N-1;
	
	while(left <= right){
		int mid = (left + right)/2;
		
		if (uniq[mid] < target) left =mid+1;
		else if(uniq[mid]==target) return mid ;
		else right = mid-1;
	}
	return -1; 
}



int main(void){
	int N,D; 
	int A[MAX]={0}, sortA[MAX]={0}, uniq[MAX]={0}, freqL[MAX]={0}, freqR[MAX]={0}; 
	int M=0;
	long long ans = 0;
	int MAX_number=0;
	scanf("%d", &N); scanf("%d", &D); 
	
	for(int l = 0; l < N ; l++){
		scanf("%d", &A[l]); 
		sortA[l] = A[l]; 
	} 
	
	qsort(sortA, N, sizeof(int), cmp_ll); 
	
	for(int l= 0; l < N ; l++){ 
		if(l == 0 || sortA[l] != sortA[l-1]){
			uniq[M]=sortA[l]; 
			M++; 
		}
		freqR[M-1]++;
	}
	
	for(int l = 0; l < N ;l++){
		int x=A[l];
		int idR = find(M, x, uniq);
		freqR[idR]--;
		int i = find(M, x-D, uniq);
		int k = find(M, x+D, uniq);
		
		if(i != -1 && k != -1){
			ans += freqL[i]* freqR[k];
		}
	freqL[idR]++;
	}
	printf("%lld", ans);	
	return 0;
}