source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in Actual solution is at the top
   *
   * @author MaxHeap
   */
  public class Main {
  
    public static void main(String[] args) {
      InputStream inputStream = System.in;
      OutputStream outputStream = System.out;
      InputReader in = new InputReader(inputStream);
      PrintWriter out = new PrintWriter(outputStream);
      TaskA solver = new TaskA();
      solver.solve(1, in, out);
      out.close();
    }
  
    static class TaskA {
  
      public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int d = in.nextInt();
        Set<Integer> pts = new HashSet<>();
        int[] x = in.nextIntArray(n);
        for (int i = 0; i < n; i++) {
          pts.add(x[i] - d);
          pts.add(x[i] + d);
        }
        Set<Integer> ans = new HashSet<>();
        for (int pt : pts) {
          int min = (int) (1e9 + 10);
          for (int i = 0; i < n; i++) {
            min = Math.min(Math.abs(x[i] - pt), min);
          }
          if (min >= d) {
            ans.add(pt);
          }
        }
        out.println(ans.size());
      }
  
    }
  
    static class InputReader {
  
      private InputStream stream;
      private byte[] buf = new byte[1 << 13];
      private int curChar;
      private int numChars;
  
      public InputReader(InputStream stream) {
        this.stream = stream;
      }
  
      public int read() {
        if (this.numChars == -1) {
          throw new UnknownError();
        } else {
          if (this.curChar >= this.numChars) {
            this.curChar = 0;
  
            try {
              this.numChars = this.stream.read(this.buf);
            } catch (IOException ex) {
              throw new InputMismatchException();
            }
  
            if (this.numChars <= 0) {
              return -1;
            }
          }
  
          return this.buf[this.curChar++];
        }
      }
  
      public int nextInt() {
        int c;
        for (c = this.read(); isSpaceChar(c); c = this.read()) {
        }
  
        byte sgn = 1;
        if (c == 45) {
          sgn = -1;
          c = this.read();
        }
  
        int res = 0;
  
        while (c >= 48 && c <= 57) {
          res *= 10;
          res += c - 48;
          c = this.read();
          if (isSpaceChar(c)) {
            return res * sgn;
          }
        }
  
        throw new InputMismatchException();
      }
  
      public static boolean isSpaceChar(int c) {
        return c == 32 || c == 10 || c == 13 || c == 9 || c == -1;
      }
  
      public int[] nextIntArray(int n) {
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
          arr[i] = nextInt();
        }
        return arr;
      }
  
    }
  }
  
  