world_of_differences.py

m, n  = raw_input().split()
m  = int(m)
n  = int(n)

e_list = []
e_list = raw_input().split()

combination = [(e_list[i],e_list[j]) for i in range(len(e_list)) for j in range(i+1, len(e_list))]

difference = []

for e in combination:
	difference.append(abs(int(e[0]) - int(e[1])))


count = 0
for d in difference:
	if d == n:
		count+=1
print count