from bisect import bisect_left
N,M = map(int,input().split())
A = sorted(list(map(int,input().split())))
ans = 0
if M%2==0:
    for i in range(N):
        if A[i]>M//2:break
        j = bisect_left(A,A[i]+M//2)
        if j<N and A[j]==A[i]+M//2:
            ans += N-2
print(ans)