from collections import *
from functools import *
from itertools import *
from heapq import *
import sys,math
input = sys.stdin.buffer.readline

N,M = map(int,input().split())
A = list(map(int,input().split()))

A.sort()
ans = 0
SA = set(A)
if M%2:
    print(0)
    exit()
for a in A:
    
    if a + M//2 in SA:
        ans += N-2
print(ans)