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 ≤ 105; 1 ≤ d ≤ 109). The next line contains n integers x1, x2, ..., xn, their absolute value doesn't exceed 109 — 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}.
import java.io.IOException;
import java.io.InputStream;
import java.util.InputMismatchException;

public class M {

	void solve()
	{
		int n = ni();
		if(n<3)
		{
			System.out.println(0);
			return;
		}
		int d = ni();
		int[] a = ia(n);
		int p1 = 0;
		int p2 = 1;
		int[] mem = new int[n];
		while(p1<n)
		{
			while(p2<n && a[p2]-a[p1]<=d)
				p2++;
			mem[p1] = p2-p1;
			p1++;
		}
		long ans = 0;
		for(int i=0;i<n;i++)
		{
			if(mem[i]>2)
			{
				ans += ((long)(mem[i]-1)*(mem[i]-2)/2);
			}
		}
		System.out.println(ans);
	}
	
	public static void main(String[] args){new M().solve();}
	
	private byte[] bufferArray = new byte[1024];
	private int bufLength = 0;
	private int bufCurrent = 0;
	InputStream inputStream = System.in;
	
	int nextByte()
	{
		if(bufLength==-1)
			throw new InputMismatchException();
		if(bufCurrent>=bufLength)
		{
			bufCurrent = 0;
			try
			{bufLength = inputStream.read(bufferArray);}
			catch(IOException e)
			{ throw new InputMismatchException();}
			if(bufLength<=0)
				return -1;
		}
		return bufferArray[bufCurrent++];
	}
	
	boolean isSpaceChar(int x)
	{return (x<33 || x>126);}
	
	boolean isDigit(int x)
	{return (x>='0' && x<='9');}
	
	int nextNonSpace()
	{
		int x;
		while((x=nextByte())!=-1 && isSpaceChar(x));
		return x;
	}
	
	int ni()
	{
		int ans = 0;
		int sign = 1;
		int x = nextNonSpace();
		if(x=='-') 
		{
			sign = -1;
			x = nextByte();
		}
		while(!isSpaceChar(x))
		{
			if(isDigit(x))
			{
				ans = ans*10 + x -'0';
				x = nextByte();
			}
			else
				throw new InputMismatchException();
		}
		return sign*ans;
	}
	
	long nl()
	{
		long ans = 0;
		long sign = 1;
		int x = nextNonSpace();
		if(x=='-') 
		{
			sign = -1;
			x = nextByte();
		}
		while(!isSpaceChar(x))
		{
			if(isDigit(x))
			{
				ans = ans*10 + x -'0';
				x = nextByte();
			}
			else
				throw new InputMismatchException();
		}
		return sign*ans;
	}
	
	String ns()
	{
		StringBuilder sb = new StringBuilder();
		int x = nextNonSpace();
		while(!isSpaceChar(x))
		{
			sb.append((char)x);
			x = nextByte();
		}
		return sb.toString();
	}
	
	String nL()
	{
		StringBuilder sb = new StringBuilder();
		int x = nextNonSpace();
		while(x==32 || !isSpaceChar(x))
		{
			sb.append((char)x);
			x = nextByte();
		}
		return sb.toString();
	}
	
	char nc()
	{ return (char)nextNonSpace();}
	
	double nd()
	{ return (double)Double.parseDouble(ns()); }
	
	char[] ca()
	{ return ns().toCharArray();}
	
	char[] ca(int n)
	{
		char[] ans = new char[n];
		int p =0;
		int x = nextNonSpace();
		while(p<n)
		{
			ans[p++] = (char)x;
			x = nextByte();
		}
		return ans;
	}
	
	int[] ia(int n)
	{
		int[] ans = new int[n];
		for(int i=0;i<n;i++)
			ans[i]=ni();
		return ans;
	}
	
}
