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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import static java.lang.Math.*;
import static java.lang.System.out;
import java.util.*;
import java.io.PrintStream;
import java.io.PrintWriter;
public class A {
 
	static final int mod = 1000000007;
	static final long temp = 998244353;
	static final long MOD = 1000000007;
	static final long M = (long)1e9+7;
 
	
	static class Pair implements Comparable<Pair>
	{
		int first, second;
		public Pair(int aa, int bb)
		{
			first = aa; second = bb;
		}
		public int compareTo(Pair p)
		{
			if(first == p.first) return (int)(second - p.second);
			return (int)(first - p.first);
		}
	}
	
	/*
	 * IO FOR 2D GRID IN JAVA
	 * 	char[][] grid = new char[n][m];
			for(int i = 0;i<n;i++)
			{
				char[] s = sc.next().toCharArray();
				for(int j = 0;j<m;j++)
				{
					grid[i][j] = s[j];
				}
			}
	 * */
	
	static class Reader {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		int[] readArray(int n) throws IOException {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		
		long[] longReadArray(int n) throws IOException {
			long[] a=new long[n];
			for (int i=0; i<n; i++) a[i]=nextLong();
			return a;
		}
		
		
		long nextLong() {
			return Long.parseLong(next());
		}
		double nextDouble() {
			return Double.parseDouble(next());
		}
	}
	
 
		public static boolean isPrime(int n) 
		{
			if(n == 1)
			{
				return false;
			}
			for(int i = 2;i*i<=n;i++)
			{
				if(n%i == 0)
				{
					return false;
				}
			}
			return true;
	}
	
	public static List<Integer> SieveList(int n)
	{
		boolean prime[] = new boolean[n+1];
		Arrays.fill(prime, true);
		
		List<Integer> l = new ArrayList<>();
		for (int p=2; p*p<=n; p++) 
		{ 
			if (prime[p] == true) 
			{ 	
			    for(int i=p*p; i<=n; i += p) 
				{
				    prime[i] = false; 
				}	
			} 
		} 
 
		for (int p=2; p<=n; p++) 
		{
		    if (prime[p] == true)
		    {
		       l.add(p); 
		    }
		}
		
		return l;
	}
	
	
	public static int gcd(int a, int b)
	{
		if(b == 0)
		 return a;
		
		else
		return gcd(b,a%b);
	} 
 
		public static int lcm(int a, int b)
	    {
	        return (a / gcd(a, b)) * b;
	    }
	
	public static long LongGCD(long a, long b)
	{
		if(b == 0)
			 return a;
			
			else
			return LongGCD(b,a%b);
	}
	
		public static long LongLCM(long a, long b)
	    {
	        return (a / LongGCD(a, b)) * b;
	    }
	
		public static int phi(int n)  //euler totient function
	    { 
	        int result = 1; 
	        for (int i = 2; i < n; i++) 
	            if (gcd(i, n) == 1) 
	                result++; 
	        return result; 
	    }
	
	public static long fastPow(long x, long n) //include mod at each step if asked and in args of fn too
	{
		if(n == 0)
			return 1;
		else if(n%2 == 0)
			return fastPow(x*x,n/2);
		else
			return x*fastPow(x*x,(n-1)/2);
	}
	
	
	   public static long modPow(long x, long y, long p)
	    {
	        long res = 1;
	        x = x % p;
	 
	        while (y > 0) {
	            if (y % 2 == 1)
	                res = (res * x) % p;
	 
	            y = y >> 1; 
	            x = (x * x) % p;
	        }
	        return res;
	    }
	   
	   static long modInverse(long n, long p)
	    {
	        return modPow(n, p - 2, p);
	    }
	 
	    // Returns nCr % p using Fermat's little theorem.
	    
	    public static long nCrModP(long n, long r,long p)
	    {
	          if (n<r) 
	              return 0;
	          
	        if (r == 0)
	            return 1;
	 
	        long[] fac = new long[(int)(n) + 1];
	        fac[0] = 1;
	 
	        for (int i = 1; i <= n; i++)
	            fac[i] = fac[i - 1] * i % p;
	 
	        return (fac[(int)(n)] * modInverse(fac[(int)(r)], p)
	                % p * modInverse(fac[(int)(n - r)], p)
	                % p)
	            % p;
	    }
	    
	    public static long nCr(long n, long r)
	    {
	    	long ans = 1;
	    	for(long i = 1,j = n;i<=r;i++,j--)
	    	{
	    		ans = ans * j / i;
	    	}
	    	return ans;
	    }
 
		public static void Sort(int[] a) {
			List<Integer> l=new ArrayList<>();
			for (int i : a) l.add(i);
			Collections.sort(l);
//			Collections.reverse(l);  //Use to Sort decreasingly 
			for (int i=0; i<a.length; i++) a[i]=l.get(i);
		}
		
		public static void ssort(char[] a)
		{
			List<Character> l = new ArrayList<>();
			for (char i : a) l.add(i);
			Collections.sort(l);
			for (int i=0; i<a.length; i++) a[i]=l.get(i);
		}
		
		
		//Modular Operations for Addition and Multiplication. 
		
		   public static long perfomMod(long x)
		   {
		        return ((x%M + M)%M);
		    }
		   public static long addMod(long a, long  b)
		   {
		        return perfomMod(perfomMod(a)+perfomMod(b));
		    }
		   public static long mulMod(long  a, long b)
		   {
		        return perfomMod(perfomMod(a)*perfomMod(b));
		   }
		
		   public static int LowerBound(int a[], int x) 
		   {
				  int l=-1,r=a.length;
				  while(l+1<r) {
				    int m=(l+r)>>>1;
				    if(a[m]>=x) r=m;
				    else l=m;
				  }
				  return r;
			}
		
		   
			public static int UpperBound(int a[], int x) 
			{
			    int l=-1;
			    int r=a.length;
			    while(l+1<r) {
			       int m=(l+r)>>>1;
			       if(a[m]<=x) l=m;
			       else r=m;
			    }
			    return l+1;
		}
	
			public static class DSU
			{
				int[] parent;
				int[] rank; //Size of the trees is used as the rank
				public DSU(int n)
				{
					parent = new int[n];
					rank = new int[n];
					Arrays.fill(parent, -1);
					Arrays.fill(rank, 1);
				}
				
				public int find(int i) //finding through path compression
				{
					return parent[i] < 0 ? i : (parent[i] = find(parent[i]));
				}
				
				public boolean union(int a, int b)
				{
					a = find(a);
					b = find(b);
					
					if(a == b) return false; //if they are already connected we exit by returning false.
					
					if(parent[a] == parent[b]) parent[a]--;
					if(parent[a] <= parent[b]) 
					{
						// a would be parent
						rank[a] += rank[b];
						parent[b] = a;
					}
					else
					{
						//b would be parent
						rank[b] += rank[a];
						parent[a] = b;
					}
					return true;
				}	
			}
		
		
	
	public static void main(String[] args) throws IOException 
	{
		Reader sc = new Reader();
		PrintWriter fout = new PrintWriter(System.out);
		    
		int n = sc.nextInt(), k = sc.nextInt();
		int[] a = sc.readArray(n);
		
		long ans = 0;
		int j = 0;
		for(int i = 0;i<n;i++)
		{
			while(j < n && (a[j] - a[i]) <= k)
			{
				j++;
			}
			long curr = (j - i - 2);
			ans += (curr * (curr + 1))/2;
		}
		
		fout.println(ans);
		
		fout.close();
	}
}