N, M = map(int, input().split())
A = list(map(int, input().split()))
if M % 2 :
    exit(print(0))
st = set()
for i in range(N):
    st.add(A[i])

ans = 0
for i in range(N):
    if A[i] + M // 2 in st:
        ans += N - 2
print(ans)