import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
n, m = na()

if m % 2:
    print(0)
    exit()
a = na()
s = set(a)
ans = 0
for i in range(n):
    if a[i] + m//2 in s:
        ans += 1

print(ans*(n-2))