n,x = map(int, input().split())
a = list(map(int, input().split()))

mxa=max(a)
cnts=[0]*(mxa+1)

for i in range(n):
    cnts[a[i]]+=1
ans=0
for i in range(n):
    nokori = x-i
    if 0<=nokori<=mxa:
        cnt=cnts[i]*cnts[nokori]
        if nokori!=i:
            cnt*=2
        ans+=cnt
print(ans)