n, m = [int(x) for x in input().split()]
a = [int(x) for x in input().split()]
a = set(a)
if m % 2 == 1:
	print(0)
	exit()
ans = 0
for ai in a:
	if ai - m // 2 in a:
		ans += 1
print(ans * (n - 2))