N, D = map(int, input().split())
A :list[int]= list(map(int, input().split()))
res=0
mag=0
for i in range(N-2):
    n=len(A)-1
    mag+=1
    base=A.pop(0)
    if A[0]==base:
        continue
    if not base+D in A:
        mag=0
        continue
    start=A.index(base+D)
    j=0
    if start>n-2:
        mag=0
        continue
    while A[start+j]==base+D:
        j+=1
        if start+j>n-1:
            break
    mag*=j
    if not base+D*2 in A[start:]:
        mag=0
        continue
    j=0
    start=A.index(base+D*2)
    while A[start+j]==base+D*2:
        j+=1
        if start+j>n-1:
            break
    mag*=j
    res+=mag
    mag=0
print(res)