# 直径が何個あるか
# M%2=1なら0

N, M = map(int, input().split())
A = list(map(int, input().split()))
A.sort()
A_set = set(A)
if M%2 == 1:
    print(0)
else:
    ans = 0
    for a in A:
        if a+M//2 in A_set:
            ans += N-2
    print(ans)