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.*;
import java.math.BigInteger;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class Contest {
	
	
	
	
	public static int gcd(int n1, int n2)
    {
        if (n2 != 0)
            return gcd(n2, n1 % n2);
        else
            return n1;
    }
	
//////////////////	
	
	
	static class pair {
        Integer x,y;
        pair (int x,int y){
            this.x=x;
            this.y=y;
        }
    }
	
//////////////////	
	
	static class length implements Comparator<String>
	{
		public int compare(String a,String b)
		{
			return(a.length()-b.length());
		}
	}
	
	
//////////////////
	
	
	
	
	
	   static class FastReader
	   {
		   BufferedReader br;
		   StringTokenizer st;
		   public FastReader()
		   {
			   br = new BufferedReader(new InputStreamReader(System.in));
		   }
		   
		   
		   String next() 
	        { 
	            while (st == null || !st.hasMoreElements()) 
	            { 
	                try
	                { 
	                    st = new StringTokenizer(br.readLine()); 
	                } 
	                catch (IOException  e) 
	                { 
	                    e.printStackTrace(); 
	                } 
	            } 
	            return st.nextToken(); 
	        } 
		   
		   
		   int nextInt()
		   {
			   return Integer.parseInt(next());
		   }
		   long nextLong()
		   {
			   return Long.parseLong(next());
		   }
		   double nextDouble() 
	        { 
	            return Double.parseDouble(next()); 
	        } 
		   
		   String nextLine() 
	        { 
	            String str = ""; 
	            try
	            { 
	                str = br.readLine(); 
	            } 
	            catch (IOException e) 
	            { 
	                e.printStackTrace(); 
	            } 
	            return str; 
	        } 
	   }
	   
////////////////////// 
	   
	  public static long Divisors(long n) 
	   { 
	       // Note that this loop runs till square root 
		   long sum=0;
	       for (int i=1; i*i<=(n); i++) 
	       { 
	           if (n%i == 0) 
	           { 
	               // If divisors are equal, print only one 
	               if (n/i == i) 
	               {
	                  // printf("%d ", i); 
	            	   sum=sum+1;
	               }
	     
	               else // Otherwise print both 
	               {
	                   //printf("%d %d ", i, n/i); 
	            	   sum=sum+2;
	               }
	           } 
	       } 
	       return(sum);
	   } 
	   
/////////////////////	  
	  
	  public static long SmallestPrimeDivisor(long n) 
	  { 
	      // if divisible by 2 
	      if (n % 2 == 0) 
	          return 2; 
	    
	      // iterate from 3 to sqrt(n) 
	      for (long i = 3; i * i <= n; i += 2) { 
	          if (n % i == 0) 
	              return i; 
	      } 
	    
	      return n; 
	  } 
	    
////////////////////	  
	   
	   public static boolean isprime(long n)
	    {
	        int count=0;
	     
	        for(long i=2;i*i<=n;i++)
	        {
	            if(n%i==0)
	            {
	                return(false);
	            }
	        }
	        return(true);
	    }
	
	   
//////////////////////
	   
	     //   (x^n)%1000000007
	   public static long modularExponentiation(long x,long n,long M)
	   {
	       if(n==0)
	           return 1;
	       else if(n%2 == 0)        //n is even
	           return modularExponentiation((x*x)%M,n/2,M);
	       else                             //n is odd
	           return (x*modularExponentiation((x*x)%M,(n-1)/2,M))%M;

	   }
	   
	   public static long nCr(int n,int k)
	   {
		  if(k==0)
			  return 1;
		  return(n*nCr(n-1,k-1)/k);
	   }
	   
	 
	   
	   

		public static void main(String []args) throws Exception
		{
			
			
			 FastReader in =new FastReader();	
			 PrintWriter pw = new PrintWriter(System.out);
		//	StringBuffer s=new StringBuffer(in.nextLine());
			int n=in.nextInt();
			int d=in.nextInt();
			int a[]=new int[n];
			long ans=0;
			for(int i=0;i<n;i++)
			{
				a[i]=in.nextInt();
			}
			if(n<3)
			{
				pw.println(0);
			}
			else
			{
				int left=0,right=2;
				while(right<n)
				{
					long x=Math.abs(a[right]-a[left]);
					if(x<=d)
					{
						long y=right-left-1;
						ans=ans+((y*(y+1))/2);
						right++;
					}
					else
					{
						left++;
					}
					if(right-left<2)
					{
						right++;
					}
					
					/*
					while(x>d)
					{
						left++;
						if( right-left<2)
						{
							left--;
							break;
							
						}
						x=Math.abs(a[right]-a[left]);
						
					}
					if(x<=d)
					{
						ans+=right-left-1;
						right++;
					}
					else
					{
						left++;
					}
					if(right-left<2)
					{
						right++;
					}
					if(right==n)
					{
						left++;
						while(right-left>=2)
						{
							x=Math.abs(a[right-1]-a[left]);
							ans+=right-1-left-1;
							left++;
							
						}
					}
					*/
					
				}
				pw.println(ans);

			}
		    
	        pw.flush();
			pw.close();
			
			
			
			
	}
		
		
}		
		
		
		
		
		
		
		
	

