# import bisect
# import heapq

## deque, defaultdict, Counter
# from collections import 

## SortedList, SortedDict, SortedSet
# from sortedcontainers import 

## itertools, combinations, permutations
# from itertools import 

# from atcoder import


def solve():
    n,d = map(int, input().split())
    a = list(map(int, input().split()))

    ans = 0

    for i in range(n):
        ai = a[i]
        for j in range(i+1, n):
            if a[j] - ai != d:
                continue
            aj = a[j]
            for k in range(j+1, n):
                if a[k] - aj == d:
                    ans += 1
    print(ans)
    

if __name__ == "__main__":
    solve()