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

cnt=0
for i in range(N):
    for j in range(i, N):
        for k in range(j, N):
            if A[i] < A[j] <A[k] and A[j] - A[i] == A[k] -A[j] == D:
                cnt +=1
print(cnt)