from collections import defaultdict

n,d=map(int,input().split())
a=list(map(int,input().split()))
ans=0
front=defaultdict(int)
back=defaultdict(int)
for i in range(2,n):
    back[a[i]]+=1
front[a[0]]+=1

for i in range(1,n-1):
    if a[i]-d in front and a[i]+d in back:
        ans+=front[a[i]-d]*back[a[i]+d]
    front[a[i]]+=1
    back[a[i+1]]-=1
print(ans)