source_code: import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  
  public class Main {
  
      public static void main(String[] args) throws IOException {
  	// write your code here
          BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
          String[] s = reader.readLine().split(" ");
          int n = Integer.parseInt(s[0]);
          int d = Integer.parseInt(s[1]);
  
          List<Integer> list = new ArrayList<>();
          s = reader.readLine().split(" ");
          for (int i = 0; i < n; i++) {
              list.add(Integer.parseInt(s[i]));
          }
  
          HashSet<Integer> set = new HashSet<>();
          for (Integer i : list) {
              set.add(i - d);
              set.add(i + d);
          }
  
          HashSet<Integer> set2 = new HashSet<>();
  
          for (Integer i : set) {
              for (Integer x : list) {
                  if (Math.abs(i - x) < d) {
                      set2.add(i);
              }
              }
          }
  
          set.removeAll(set2);
          System.out.println(set.size());
  
      }
  }
  