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()
a = a + [m + x for x in a]

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