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()

assert m % 2 == 0
a = na()

j = 0
ans = 0
#print(a)
for i in range(n ):
    while j < n and a[j] - a[i] < m//2:
        j += 1
    if j < n and a[j] - a[i] == m//2:
        ans += 1
        #print(i, j)
print(ans*(n-2))