import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)


#alist = []
#s = input()
n,m = map(int,input().split())
if m %2:
    exit(print(0))
#for i in range(n):
#    alist.append(list(map(int,input().split())))
alist = list(map(int,input().split()))
s = set(alist)
ans = 0
for i in alist:
    if i + m//2 in s:
        ans += n-2
print(ans)