Little Petya likes points a lot. Recently his mom has presented him n points lying on the line OX. Now Petya is wondering in how many ways he can choose three distinct points so that the distance between the two farthest of them doesn't exceed d.

Note that the order of the points inside the group of three chosen points doesn't matter.


-----Input-----

The first line contains two integers: n and d (1 ≤ n ≤ 10^5; 1 ≤ d ≤ 10^9). The next line contains n integers x_1, x_2, ..., x_{n}, their absolute value doesn't exceed 10^9 — the x-coordinates of the points that Petya has got.

It is guaranteed that the coordinates of the points in the input strictly increase.


-----Output-----

Print a single integer — the number of groups of three points, where the distance between two farthest points doesn't exceed d.

Please do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.


-----Examples-----
Input
4 3
1 2 3 4

Output
4

Input
4 2
-3 -2 -1 0

Output
2

Input
5 19
1 10 20 30 50

Output
1



-----Note-----

In the first sample any group of three points meets our conditions.

In the seconds sample only 2 groups of three points meet our conditions: {-3, -2, -1} and {-2, -1, 0}.

In the third sample only one group does: {1, 10, 20}.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = '"""\nProblem 2, Points on Line\nSizhang Zhao 1200011770\n"""\nfrom collections import deque\n\ndef number(D, d, length, tem):\n\tif tem < length:\n\t\tif tem == 0:\n\t\t\tstart = 1\n\t\t\tnum = 0\n\t\telse:\n\t\t\tstart = tem \n\t\t\tnum = tem - 1\n\t\tfor i in range(start, length):\n\t\t\tif D[i] - D[0] <= d:\n\t\t\t\tnum += 1\n\t\t\telse:\n\t\t\t\tbreak\n\telse:\n\t\tnum = tem - 1\n\tif num < 2:\n\t\treturn 0\n\telse:\n\t\treturn num \n\nn, d = [int(i) for i in input().split()]\nnumbers = [int(i) for i in input().split()]\nD = deque(numbers)\nleng = len(D)\ntimes = 0\ntem = 0\nwhile leng >= 3:\n\tleng = len(D)\n\ttem = number(D, d, leng, tem)\n\ttimes += tem * (tem - 1) / 2 \n\tD.popleft()\nprint(int(times))\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 13975