n, m = map(int, input().split())
aa = list(map(int, input().split()))

if m % 2 == 1:
    print(0)
    exit(0)

cnt = 0
s = set()
for a in sorted(aa):
    if a <= m / 2:
        s.add(a)
    elif a - m / 2 in s:
        cnt += 1

print(cnt * (n - 2))