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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author sumit
 */
public class Main {
      public static void main(String[] args) {
            InputStream inputStream = System.in;
            OutputStream outputStream = System.out;
            InputReader in = new InputReader(inputStream);
            OutputWriter out = new OutputWriter(outputStream);
            APointsOnLine solver = new APointsOnLine();
            solver.solve(1, in, out);
            out.close();
      }

      static class APointsOnLine {
            int search(int start, int end, int arr[], int val) {
                  int mid = (start + end) / 2;
                  if (start > end)
                        return Integer.MAX_VALUE;
                  if (arr[mid] > val) {
                        return Math.min(mid, search(start, mid - 1, arr, val));
                  } else if (arr[mid] < val) {
                        return search(mid + 1, end, arr, val);
                  } else {
                        return mid;
                  }
            }

            public void solve(int testNumber, InputReader in, OutputWriter out) {
                  int n = in.nextInt();
                  int d = in.nextInt();
                  int[] arr = in.nextIntArray(n);
                  long ans = 0;
                  for (int i = 0; i < n; i++) {
                        int l = search(0, n - 1, arr, arr[i] - d);
                        ans += ((long) (i - l) * (i - l - 1)) / 2;
                  }
                  out.printLine(ans);


            }

      }

      static class InputReader {
            private InputStream stream;
            private byte[] buf = new byte[1024];
            private int curChar;
            private int numChars;

            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 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 & 15;

                        c = read();
                  } while (!isSpaceChar(c));

                  return res * sgn;
            }

            public int[] nextIntArray(int arraySize) {
                  int array[] = new int[arraySize];

                  for (int i = 0; i < arraySize; i++)
                        array[i] = nextInt();

                  return array;
            }

            public boolean isSpaceChar(int c) {
                  return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
            }

      }

      static class OutputWriter {
            private final PrintWriter writer;

            public OutputWriter(OutputStream outputStream) {
                  writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
            }

            public OutputWriter(Writer writer) {
                  this.writer = new PrintWriter(writer);
            }

            public void close() {
                  writer.close();
            }

            public void printLine(long i) {
                  writer.println(i);
            }

      }
}

