source_code: import java.io.*;
  import java.util.*;
  
  public class A implements Runnable{
  	public static void main (String[] args) {new Thread(null, new A(), "_cf", 1 << 28).start();}
  
  	public void run() {
  		FastScanner fs = new FastScanner();
  		PrintWriter out = new PrintWriter(System.out);
  		System.err.println("Go!");
  
  		int n = fs.nextInt();
  		int d = fs.nextInt();
  		int[] a = fs.nextIntArray(n);
  		sort(a);
  		long res = 0;
  		if(n == 1) {
  			System.out.println(2);
  			return;
  		}
  
  		HashSet<Integer> set = new HashSet<>();
  		for(int i = 0; i < n; i++) {
  			int one = a[i] - d;
  			int min = Integer.MAX_VALUE;
  			for(int j = 0; j < n; j++) {
  				int dist = Math.abs(a[j] - one);
  				min = Math.min(min, dist);
  			}
  			if(min == d) set.add(one);
  			one = a[i] + d;
  			min = Integer.MAX_VALUE;
  			for(int j = 0; j < n; j++) {
  				int dist = Math.abs(a[j] - one);
  				min = Math.min(min, dist);
  			}
  			if(min == d) set.add(one);
  		}
  		System.out.println(set.size());
  		out.close();
  	}
  
  	void sort (int[] a) {
  		int n = a.length;
  		for(int i = 0; i < 50; i++) {
  			Random r = new Random();
  			int x = r.nextInt(n), y = r.nextInt(n);
  			int temp = a[x];
  			a[x] = a[y];
  			a[y] = temp;
  		}
  		Arrays.sort(a);
  	}
  
  	class FastScanner {
  		public int BS = 1<<16;
  		public char NC = (char)0;
  		byte[] buf = new byte[BS];
  		int bId = 0, size = 0;
  		char c = NC;
  		double num = 1;
  		BufferedInputStream in;
  
  		public FastScanner() {
  			in = new BufferedInputStream(System.in, BS);
  		}
  
  		public FastScanner(String s) throws FileNotFoundException {
  			in = new BufferedInputStream(new FileInputStream(new File(s)), BS);
  		}
  
  		public char nextChar(){
  			while(bId==size) {
  				try {
  					size = in.read(buf);
  				}catch(Exception e) {
  					return NC;
  				}                
  				if(size==-1)return NC;
  				bId=0;
  			}
  			return (char)buf[bId++];
  		}
  
  		public int nextInt() {
  			return (int)nextLong();
  		}
  
  		public long nextLong() {
  			num=1;
  			boolean neg = false;
  			if(c==NC)c=nextChar();
  			for(;(c<'0' || c>'9'); c = nextChar()) {
  				if(c=='-')neg=true;
  			}
  			long res = 0;
  			for(; c>='0' && c <='9'; c=nextChar()) {
  				res = (res<<3)+(res<<1)+c-'0';
  				num*=10;
  			}
  			return neg?-res:res;
  		}
  
  		public double nextDouble() {
  			double cur = nextLong();
  			return c!='.' ? cur:cur+nextLong()/num;
  		}
  
  		public String next() {
  			StringBuilder res = new StringBuilder();
  			while(c<=32)c=nextChar();
  			while(c>32) {
  				res.append(c);
  				c=nextChar();
  			}
  			return res.toString();
  		}
  
  		public String nextLine() {
  			StringBuilder res = new StringBuilder();
  			while(c<=32)c=nextChar();
  			while(c!='\n') {
  				res.append(c);
  				c=nextChar();
  			}
  			return res.toString();
  		}
  
  		public boolean hasNext() {
  			if(c>32)return true;
  			while(true) {
  				c=nextChar();
  				if(c==NC)return false;
  				else if(c>32)return true;
  			}
  		}
  		
  		public int[] nextIntArray(int n) {
  			int[] res = new int[n];
  			for(int i = 0; i < n; i++) res[i] = nextInt();
  			return res;
  		}
  		
  	}
  
  }