import bisect

N, X = map(int, input().split())
As = list(map(int, input().split()))

As.sort()

count = 0
for a in As:
    idx = bisect.bisect_left(As, X - a)
    loop = 0
    while True:
        if idx + loop < N and As[idx + loop] == X - a:
            count += 1
            loop += 1
        else:
            break
print(count)