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}.
/*
 * DA-IICT
 * Author: Jugal Kalal
 */
import java.util.*;
import java.io.*;
import java.math.*;
import java.text.DecimalFormat;
public class Hackerearth{
	static long mod=(long)Math.pow(10,9)+7;
	public static void main(String args[]) {
        new Thread(null, new Runnable() {
            public void run() {
                try{
                    solve();
                    w.close();
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        }, "1", 1 << 26).start();
	}
	static InputReader in;
    static PrintWriter w;
    static void solve(){
        in = new InputReader(System.in);
        w = new PrintWriter(System.out);
        int n=in.nextInt(),d=in.nextInt();
        int arr[]=in.nextIntArray(n);
        int j=0;
        long ans=0;
        for(int i=0;i<n;i++){
        		while(arr[i]-arr[j]>d) {
        			j++;
        		}
        		ans+=(i-j)*1l*(i-j-1)/2;
        }
        w.println(ans);
    }
    static int findceil(int arr[],int pos) {
    		int l=0,r=arr.length-1;
    		int ans=0;
    		while(l<=r) {
    			int mid=(l+r)>>1;
    			if(arr[mid]>=pos) {
    				ans=mid;
    				r=mid-1;
    			}else {
    				l=mid+1;
    			}
    		}
    		return ans;
    }
    static int findfloor(int arr[],int pos) {
    		int l=0,r=arr.length-1;
    		int ans=arr.length-1;
    		while(l<=r) {
    			int mid=(l+r)>>1;
    			if(pos>=arr[mid]) {
    				ans=mid;
    				l=mid+1;
    			}else {
    				r=mid-1;
    			}
    		}
    		return ans;
    }
    static class Pair{
    		int l;
    		int r;
    		public Pair(int l,int r) {
    			this.l=l;
    			this.r=r;
    		}
    }
    static ArrayList<Integer> adj[]; //Adjacency Lists
    static int V;   // No. of vertices
    // Constructor
    static void Graph(int v){
        V = v;
        adj = new ArrayList[v];
        for (int i=0; i<v; ++i){
        		adj[i] = new ArrayList();
        }
    }
    
    // Function to add an edge into the graph
    static void addEdge(int u,int v){
		adj[u].add(v);
		adj[v].add(u);
    }
//    static long[] isHamiltonian_path(int n){
//    	boolean dp[][]=new boolean[n][1<<n];
//    	long ans[]=new long[n];
//    	long sum[]=new long[n];
//    	for(int i=0;i<n;i++){
//    		dp[i][1<<i]=true;
//    		ans[i]=0;
//    		sum[i]=i+1;
//    	}
//    	for(int mask=0;mask<(1<<n);mask++){
//    		int s=0;
//    		int count=0,temp=mask;
//    		while(temp>0){
//    			s+=1+Math.log(temp&(-temp))/Math.log(2);
//    			temp=temp&(temp-1);
//    			count++;
//    		}
//    		for(int j=0;j<n;j++){
//    			if((mask&(1<<j))>0){
//    				for(int k=0;k<n;k++){
//    					if(j!=k&&(mask&(1<<k))>0&&adj[j][k]&&dp[k][mask^(1<<j)]){
//    						dp[j][mask]=true;
//    						ans[j]=Math.max(ans[j],count-1);
//    						if(ans[j]==count-1){
//    							sum[j]=Math.max(sum[j], s);
//    						}
//    					}
//    				}
//    			}
//    		}
//    	}
//    	return sum;
//    }
//    static void bfs(int s,int n){
//    	boolean visited[]=new boolean[n];
//    	LinkedList<Integer> queue=new LinkedList<Integer>();
//    	queue.add(s);
//    	visited[s]=true;
//    	while(!queue.isEmpty()){
//    		int num=queue.pop();
////    		System.out.println(ans.toString());
//    		for(int i=0;i<adj[num].size();i++){
//    			if(!visited[adj[num].get(i)]){
//    				visited[adj[num].get(i)]=true;
//    				queue.add(adj[num].get(i));
//    			}
//    		}
//    	}
//    }
    static long gcd(long a,long b){
		if(a==0){
			return b;
		}
		return gcd(b%a,a);
	}
    static long power(long base, long exponent, long modulus){
	    long result = 1L;
	    while (exponent > 0) {
	        if (exponent % 2L == 1L)
	            result = (result * base) % modulus;
	        exponent = exponent >> 1;
	        base = (base * base) % modulus;
	    }
	    return result;
	}
    static HashMap<Long,Long> primeFactors(long n){
        HashMap<Long,Long> ans=new HashMap<Long,Long>();
    	// Print the number of 2s that divide n
        while (n%2L==0L)
        {
            if(ans.containsKey(2L)){
            	ans.put(2L,ans.get(2L)+1L);
            }else{
            	ans.put(2L,1L);
            }
            n /= 2L;
        }
 
        // n must be odd at this point.  So we can
        // skip one element (Note i = i +2)
        for (long i = 3; i <= Math.sqrt(n); i+= 2L)
        {
            // While i divides n, print i and divide n
            while (n%i == 0)
            {
            	if(ans.containsKey(i)){
                	ans.put(i,ans.get(i)+1L);
                }else{
                	ans.put(i,1L);
                }
                n /= i;
            }
        }
 
        // This condition is to handle the case whien
        // n is a prime number greater than 2
        if (n > 2)
            ans.put(n,1L);
        return ans;
    }
////for marking all prime numbers greater than 1 and less than equal to N
	static boolean[] sieve(int N) {
		 boolean isPrime[]=new boolean[N+1];
		 isPrime[0] = true;
		 isPrime[1] = true;
		 for(int i = 2; i * i <= N; ++i) {
		      if(isPrime[i] == false) {//Mark all the multiples of i as composite numbers
		          for(int j = i * i; j <= N ;j += i)
		              isPrime[j] = true;
		     }
		 }
		 return isPrime;
	}
//  //if  str2 (pattern) is subsequence of str1 (Text) or not
//	static boolean function(String str1,String str2){
//	     str2 = str2.replace("", ".*");  //returns .*a.*n.*n.*a.
//	     return (str1.matches(str2));  // returns true
//	}
    static int Arr[];
    static long size[];
  //modified initialize function:
    static void initialize(int N){
    	Arr=new int[N];
    	size=new long[N];
        for(int i = 0;i<N;i++){
        	Arr[ i ] = i ;
        	size[ i ] = 1;
        }
    }
    static boolean find(int A,int B){
        if( root(A)==root(B) )       //if A and B have same root,means they are connected.
        return true;
        else
        return false;
    }
 // modified root function.
    static void weighted_union(int A,int B,int n){
        int root_A = root(A);
        int root_B = root(B);
        if(size[root_A] < size[root_B ]){
        	Arr[ root_A ] = Arr[root_B];
        	size[root_B] += size[root_A];
        }
        else{
        	Arr[ root_B ] = Arr[root_A];
        	size[root_A] += size[root_B];
        }
    }
    static int root (int i){
        while(Arr[ i ] != i){
            Arr[ i ] = Arr[ Arr[ i ] ] ; 
            i = Arr[ i ]; 
        }
        return i;
    }
    
 
	static boolean isPrime(long n) {
		if(n < 2L) return false;
		if(n == 2L || n == 3L) return true;
		if(n%2L == 0 || n%3L == 0) return false;	
		long sqrtN = (long)Math.sqrt(n)+1L;
		for(long i = 6L; i <= sqrtN; i += 6L) {
			if(n%(i-1) == 0 || n%(i+1) == 0) return false;
		}
		return true;
	}
//	static HashMap<Integer,Integer> level;;
//	static HashMap<Integer,Integer> parent;
	static int maxlevel=0;
	
//	static boolean T[][][];
//	static void subsetSum(int input[], int total, int count) {
//        T = new boolean[input.length + 1][total + 1][count+1];
//        for (int i = 0; i <= input.length; i++) {
//        	T[i][0][0] = true;
//        	for(int j = 1; j<=count; j++){
//        		T[i][0][j] = false;
//        	}
//        }
//        int sum[]=new int[input.length+1];
//        for(int i=1;i<=input.length;i++){
//            sum[i]=sum[i-1]+input[i-1];
//        }
//        for (int i = 1; i <= input.length; i++) {
//            for (int j = 1; j <= (int)Math.min(total,sum[i]); j++) {
//            	for (int k = 1; k <= (int)Math.min(i,count); k++){
//            		 if (j >= input[i - 1]) {//Exclude and Include
//                         T[i][j][k] = T[i - 1][j][k] || T[i - 1][j - input[i - 1]][k-1];
//                     } else {
//                         T[i][j][k] = T[i-1][j][k];
//                     }
//            	}
//            }
//        }
//    }
//	static <K,V extends Comparable<? super V>>
//	SortedSet<Map.Entry<K,V>> entriesSortedByValues(Map<K,V> map) {
//	    SortedSet<Map.Entry<K,V>> sortedEntries = new TreeSet<Map.Entry<K,V>>(
//	        new Comparator<Map.Entry<K,V>>() {
//	            @Override public int compare(Map.Entry<K,V> e1, Map.Entry<K,V> e2) {
//	                int res = e2.getValue().compareTo(e1.getValue());
//	                return res != 0 ? res : 1;
//	            }
//	        }
//	    );
//	    sortedEntries.addAll(map.entrySet());
//	    return sortedEntries;
//	}
	
 
	 
	//minimum prime factor of all the numbers less than n
    static int minPrime[];
	static void minimumPrime(int n){
		minPrime=new int[n+1];
		minPrime[1]=1;
        for (int i = 2; i * i <= n; ++i) {
            if (minPrime[i] == 0) {         //If i is prime
                for (int j = i * i; j <= n; j += i) {
                    if (minPrime[j] == 0) {
                        minPrime[j] = i;
                    }
                }
            }
        }
        for (int i = 2; i <= n; ++i) {
            if (minPrime[i] == 0) {
                minPrime[i] = i;
            }
        }
	}
	static long modInverse(long A, long M)
	{
		long x=extendedEuclid(A,M)[0];
		return (x%M+M)%M;    //x may be negative
	}
	static long[] extendedEuclid(long A, long B) {
		if(B == 0) {
			long d = A;
			long x = 1;
			long y = 0;
			return new long[]{x,y,d};
		}
		else {
			long arr[]=extendedEuclid(B, A%B);
			long temp = arr[0];
			arr[0] = arr[1];
			arr[1] = temp - (A/B)*arr[1];
			return arr;
		}
	}
 
	static class InputReader {
        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, numChars;
        private SpaceCharFilter filter;
 
        public InputReader(InputStream stream) {
            this.stream = stream;
        }
        
        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }
 
        public String nextLine() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }
 
        public String readString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }
 
        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
 
        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
 
        public int[] nextIntArray(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextInt();
            }
            return arr;
        }
 
        public long[] nextLongArray(int n) {
            long[] arr = new long[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextLong();
            }
            return arr;
        }
 
        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
 
        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }
        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
	}
} 