from collections import defaultdict

N, D = map(int,input().split())
A = list(map(int,input().split()))

dct = [defaultdict(int) for _ in range(3)]
ans = 0

for i in range(N):
	dct[0][A[i]] += 1
	
	if dct[0][A[i]-D] > 0:
		dct[1][A[i]] += 1
	
	if dct[1][A[i]-D] > 0:
		dct[2][A[i]] += 1
		ans += dct[1][A[i]-D]*dct[0][A[i]-2*D]

print(ans)