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.util.*;

/**
 * Created by gouthamvidyapradhan on 07/07/2020
 */
public class PointsOnLine {
    private static PrintWriter pw = new PrintWriter(new BufferedOutputStream(System.out, 500000));
    static class MyScanner {
        /**
         * Buffered reader
         */
        private static BufferedReader br = new BufferedReader(
                new InputStreamReader(System.in));

        private static StringTokenizer st;

        /**
         * Read integer
         *
         * @return
         * @throws Exception
         */
        public static int readInt() throws Exception {
            try {
                if (st != null && st.hasMoreTokens()) {
                    return parseInt(st.nextToken());
                }
                String str = br.readLine();
                if(str == null) return -2;
                if (!str.trim().equals("")) {
                    st = new StringTokenizer(str);
                    return parseInt(st.nextToken());
                }
            } catch (IOException e) {
                close();
                return -1;
            }
            return -1;
        }

        /**
         * Read integer
         *
         * @return
         * @throws Exception
         */
        public static long readLong() throws Exception {
            try {
                if (st != null && st.hasMoreTokens()) {
                    return Long.parseLong(st.nextToken());
                }
                String str = br.readLine();
                if (str != null && !str.trim().equals("")) {
                    st = new StringTokenizer(str);
                    return Long.parseLong(st.nextToken());
                }
            } catch (IOException e) {
                close();
                return -1;
            }
            return -1;
        }

        /**
         * Read line
         * @return
         * @throws Exception
         */
        public static String readLine() throws Exception
        {
            return br.readLine();
        }

        /**
         * Parse to integer
         * @param in
         * @return integer value
         */
        public static int parseInt(String in)
        {
            // Check for a sign.
            int num  = 0, sign = -1, i = 0;
            final int len  = in.length( );
            final char ch  = in.charAt( 0 );
            if ( ch == '-' )
                sign = 1;
            else
                num = '0' - ch;

            // Build the number.
            i+=1;
            while ( i < len )
                num = num*10 + '0' - in.charAt( i++ );
            return sign * num;
        }

        /**
         * Close BufferedReader
         *
         * @throws Exception
         */
        public static void close() throws Exception {
            br.close();
        }
    }

    public static void main(String[] args) throws Exception{
        int n = MyScanner.readInt();
        int d = MyScanner.readInt();
        long[] A = new long[n];
        for(int i = 0; i < n; i ++){
            A[i] = MyScanner.readLong();
        }
        TreeMap<Long, Long> treeMap = new TreeMap<>(Comparator.comparingLong(o -> o));
        for(int i = 0; i < n; i ++){
            treeMap.put(A[i], (long)i);
        }
        long sum = 0L;
        for(int i = 0; i < n; i ++){
            long v = A[i] + d;
            Map.Entry<Long, Long> entry = treeMap.floorEntry(v);
            if(entry != null && entry.getKey() != A[i]){
                long k = entry.getValue();
                long a = (k - i - 1);
                a *= (a + 1);
                a /= 2;
                sum += a;
            }
        }
        pw.println(sum);
        pw.flush();
        pw.close();
    }
}
