Problem: Mad scientist Mike has just finished constructing a new device to search for extraterrestrial intelligence! He was in such a hurry to launch it for the first time that he plugged in the power wires without giving it a proper glance and started experimenting right away. After a while Mike observed that the wires ended up entangled and now have to be untangled again.

The device is powered by two wires "plus" and "minus". The wires run along the floor from the wall (on the left) to the device (on the right). Both the wall and the device have two contacts in them on the same level, into which the wires are plugged in some order. The wires are considered entangled if there are one or more places where one wire runs above the other one. For example, the picture below has four such places (top view):

<image>

Mike knows the sequence in which the wires run above each other. Mike also noticed that on the left side, the "plus" wire is always plugged into the top contact (as seen on the picture). He would like to untangle the wires without unplugging them and without moving the device. Determine if it is possible to do that. A wire can be freely moved and stretched on the floor, but cannot be cut.

To understand the problem better please read the notes to the test samples.

Input

The single line of the input contains a sequence of characters "+" and "-" of length n (1 ≤ n ≤ 100000). The i-th (1 ≤ i ≤ n) position of the sequence contains the character "+", if on the i-th step from the wall the "plus" wire runs above the "minus" wire, and the character "-" otherwise.

Output

Print either "Yes" (without the quotes) if the wires can be untangled or "No" (without the quotes) if the wires cannot be untangled.

Examples

Input

-++-


Output

Yes


Input

+-


Output

No


Input

++


Output

Yes


Input

-


Output

No

Note

The first testcase corresponds to the picture in the statement. To untangle the wires, one can first move the "plus" wire lower, thus eliminating the two crosses in the middle, and then draw it under the "minus" wire, eliminating also the remaining two crosses.

In the second testcase the "plus" wire makes one full revolution around the "minus" wire. Thus the wires cannot be untangled: 

<image>

In the third testcase the "plus" wire simply runs above the "minus" wire twice in sequence. The wires can be untangled by lifting "plus" and moving it higher: 

<image>

In the fourth testcase the "minus" wire runs above the "plus" wire once. The wires cannot be untangled without moving the device itself: 

<image>

Solution (in JAVA):

Solution:
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Arrays;
import java.util.Random;

/**
 * @author Ivan Pryvalov (ivan.pryvalov@gmail.com)
 */
public class Codeforces_R_200_Div_1_B implements Runnable{

	private void solve() throws IOException {
		String s = scanner.nextToken();
		char[] c = s.toCharArray();
		int N = c.length;
		if (N%2 != 0){
			out.println("No");
			return;
		}
		int cnt = 0;
		for(int i=0; i<N; i+=2){
			if (c[i]=='-' && c[i+1]=='+'){
				cnt++;
			}else if (c[i]=='+' && c[i+1]=='-'){
				cnt--;
			}
		}
		if (cnt==0){
			out.println("Yes");
		}else{
			out.println("No");
		}
	}

	/////////////////////////////////////////////////
	final int BUF_SIZE = 1024 * 1024 * 8;//important to read long-string tokens properly
	final int INPUT_BUFFER_SIZE = 1024 * 1024 * 8 ;
	final int BUF_SIZE_INPUT = 1024;
	
	final int BUF_SIZE_OUT = 1024;
	
	boolean inputFromFile = false;
	String filenamePrefix = "A-small-attempt0";
	String inSuffix = ".in";
	String outSuffix = ".out";
	
	PrintStream out;
	ByteScanner scanner;
	ByteWriter writer;
	
//	@Override
	public void run() {
		try{
			InputStream bis = null;
			OutputStream bos = null;
			if (inputFromFile){
				File baseFile = new File(getClass().getResource("/").getFile());
				bis = new BufferedInputStream(
						new FileInputStream(new File(
								baseFile, filenamePrefix+inSuffix)),
								INPUT_BUFFER_SIZE);
				bos = new BufferedOutputStream(
						new FileOutputStream(
								new File(baseFile, filenamePrefix+outSuffix)));
				out = new PrintStream(bos);
			}else{
				bis = new BufferedInputStream(System.in, INPUT_BUFFER_SIZE);
				bos = new BufferedOutputStream(System.out);
				out = new PrintStream(bos);
			}
			scanner = new ByteScanner(bis, BUF_SIZE_INPUT, BUF_SIZE);
			writer = new ByteWriter(bos, BUF_SIZE_OUT);
			
			solve();
			out.flush();
		}catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}
	
	public interface Constants{
		final static byte ZERO = '0';//48 or 0x30
		final static byte NINE = '9';
		final static byte SPACEBAR = ' '; //32 or 0x20
		final static byte MINUS = '-'; //45 or 0x2d	
		
		final static char FLOAT_POINT = '.';
	}
	
	public static class EofException extends IOException{
	}
	
	public static class ByteWriter implements Constants {
		
		int bufSize = 1024;
		byte[] byteBuf = new byte[bufSize];
		OutputStream os;
		
		public ByteWriter(OutputStream os, int bufSize){
			this.os = os;
			this.bufSize = bufSize;
		}
		
		public void writeInt(int num) throws IOException{
	         int byteWriteOffset = byteBuf.length;
	         if (num==0){
	        	 byteBuf[--byteWriteOffset] = ZERO;
	         }else{
	        	 int numAbs = Math.abs(num);
	        	 while (numAbs>0){
	        		 byteBuf[--byteWriteOffset] = (byte)((numAbs % 10) + ZERO);
	        		 numAbs /= 10;
	        	 }
	        	 if (num<0)
	        		 byteBuf[--byteWriteOffset] = MINUS;
	         }
	         os.write(byteBuf, byteWriteOffset, byteBuf.length - byteWriteOffset);
		}
		
		/**
		 * Please ensure ar.length <= byteBuf.length!
		 * 
		 * @param ar
		 * @throws IOException
		 */
		public void writeByteAr(byte[] ar) throws IOException{
			for (int i = 0; i < ar.length; i++) {
				byteBuf[i] = ar[i];
			}
			os.write(byteBuf,0,ar.length);
		}
		
		public void writeSpaceBar() throws IOException{
			byteBuf[0] = SPACEBAR;
			os.write(byteBuf,0,1);
		}
		
	}
	
	public static class ByteScanner implements Constants{
		
		InputStream is;
		
		public ByteScanner(InputStream is, int bufSizeInput, int bufSize){
			this.is = is;
			this.bufSizeInput = bufSizeInput;
			this.bufSize = bufSize;
			
			byteBufInput = new byte[this.bufSizeInput];
			byteBuf = new byte[this.bufSize];
		}
		
		public ByteScanner(byte[] data){
			byteBufInput = data;
			bufSizeInput = data.length;
			bufSize = data.length;
			byteBuf = new byte[bufSize];
			byteRead = data.length;
			bytePos = 0;
		}
		
		private int bufSizeInput;
		private int bufSize;
		
		byte[] byteBufInput;
		byte by=-1;
		int byteRead=-1;
		int bytePos=-1;

		byte[] byteBuf;
		int totalBytes;
		
		boolean eofMet = false;
		
		private byte nextByte() throws IOException{
			
			if (bytePos<0 || bytePos>=byteRead){
				byteRead = is==null? -1: is.read(byteBufInput);
				bytePos=0;
				if (byteRead<0){
					byteBufInput[bytePos]=-1;//!!!
					if (eofMet)
						throw new EofException();
					eofMet = true;
				}
			}
			return byteBufInput[bytePos++];
		}
		
		/**
		 * Returns next meaningful character as a byte.<br>
		 * 
		 * @return
		 * @throws IOException
		 */
		public byte nextChar() throws IOException{
			while ((by=nextByte())<=0x20);
			return by;
		}
		
		/**
		 * Returns next meaningful character OR space as a byte.<br>
		 * 
		 * @return
		 * @throws IOException
		 */
		public byte nextCharOrSpacebar() throws IOException{
			while ((by=nextByte())<0x20);
			return by;
		}
		
	    /**
	     * Reads line.
	     * 
	     * @return
	     * @throws IOException
	     */
	    public String nextLine() throws IOException {
            readToken((byte)0x20);
            return new String(byteBuf,0,totalBytes);
	    }
	    
	    public byte[] nextLineAsArray() throws IOException {
            readToken((byte)0x20);
            byte[] out = new byte[totalBytes];
            System.arraycopy(byteBuf, 0, out, 0, totalBytes);
            return out;
	    }
	    
		
	    /**
	     * Reads token. Spacebar is separator char.
	     * 
	     * @return
	     * @throws IOException
	     */
	    public String nextToken() throws IOException {
            readToken((byte)0x21);
            return new String(byteBuf,0,totalBytes);
	    }
	    
	    /**
	     * Spacebar is included as separator char
	     * 
	     * @throws IOException
	     */
	    private void readToken() throws IOException {	    	
            readToken((byte)0x21);
	    }
	    
	    private void readToken(byte acceptFrom) throws IOException {
            totalBytes = 0;
            while ((by=nextByte())<acceptFrom);
            byteBuf[totalBytes++] = by;
            while ((by=nextByte())>=acceptFrom){
                byteBuf[totalBytes++] = by;
            }
	    }
		
	    public int nextInt() throws IOException{
			readToken();
			int num=0, i=0;
			boolean sign=false;
			if (byteBuf[i]==MINUS){
				sign = true;
				i++;
			}
			for (; i<totalBytes; i++){
				num*=10;
				num+=byteBuf[i]-ZERO;
			}
			return sign?-num:num;
		}
		
		public long nextLong() throws IOException{
			readToken();
			long num=0;
			int i=0;
			boolean sign=false;
			if (byteBuf[i]==MINUS){
				sign = true;
				i++;
			}
			for (; i<totalBytes; i++){
				num*=10;
				num+=byteBuf[i]-ZERO;
			}
			return sign?-num:num;
		}
		
		/*
		//TODO test Unix/Windows formats
		public void toNextLine() throws IOException{
			while ((ch=nextChar())!='\n');
		}
		*/
		
		public double nextDouble() throws IOException{
			readToken();
			char[] token = new char[totalBytes];
			for (int i = 0; i < totalBytes; i++) {
				token[i] = (char)byteBuf[i];
			}
			return Double.parseDouble(new String(token));
		}
		
		public int[] loadIntArray(int size) throws IOException{
			int[] a = new int[size];
			for (int i = 0; i < a.length; i++) {
				a[i] = nextInt();
			}
			return a;
		}
		
		public long[] loadLongArray(int size) throws IOException{
			long[] a = new long[size];
			for (int i = 0; i < a.length; i++) {
				a[i] = nextLong();
			}
			return a;
		}
	    
	}
	
	public static abstract class Timing{
		private static int counter = 0;
		protected String name = "Timing"+(++counter);
		private boolean debug;
		
		public Timing(boolean debug) {
			super();
			this.debug = debug;
		}
		
		public abstract void run();
		public void start(){
			long time1 = System.currentTimeMillis();
			run();
			long time2 = System.currentTimeMillis();
			if (debug)
				System.out.println(name+" time = "+(time2-time1)/1000.0+" s.");
		}
		
	}
	
	public static class TimeMonitor{
		String name;
		public TimeMonitor(String name) {
			super();
			this.name = name;
		}
		long time1;
		public TimeMonitor start(){
			time1 = System.currentTimeMillis();
			return this;
		}
		public void stop(){
			long time2 = System.currentTimeMillis();
			System.out.println(name+" time = "+(time2-time1)/1000.0+" s.");
		}
	}
	
	public static class Alg{
		public static interface BooleanChecker{
			public boolean check(long arg);
		}
		
		public static class BinarySearch{
					
			/**
			 * This check returns boolean value, result of function.
			 * It should be monotonic.
			 * 
			 * @return
			 */
			public BooleanChecker bc;
			
			
			/**
			 * Returns following element: <pre> 0 0 [1] 1 1</pre>
			 */
			public long search(long left, long right){
				while (left<=right){
					long mid = (left+right)/2;
					if (bc.check(mid)){
						right = mid-1;
					}else{
						left = mid+1;
					}
				}
				return left;
			}
			
			/**
			 * Optional.<br>
			 * Returns following element: <pre> 1 1 [1] 0 0</pre>
			 */
			public long searchInverted(long left, long right){
				while (left<=right){
					long mid = (left+right)/2;
					if (!bc.check(mid)){
						right = mid-1;
					}else{
						left = mid+1;
					}
				}
				return left - 1; 
			}
		}
	}
	
	public static class Modulo{
		long mod = (long)1e9+7;
		
		public Modulo(long mod) {
			super();
			this.mod = mod;
		}

		public long inv(long a) {
			long res =  pow(a, mod-2);
			return res;
		}

		public long pow(long a, long x) {
			if (x==0)
				return 1;
			long part = 1;
			if ((x&1)!=0)
				part = a;
			return (part * pow((a*a)%mod, x>>1)) % mod;
		}
		
		public long c(long n, long m){
			long res = 1;
			for(int i=1; i<=m; i++){
				res = (res * (n-m+i)) % mod;
				res = (res * inv(i)) % mod;
			}
			return res;
		}
		
	}
	
	
	/**
	 * Added 26.04.2013. 
	 * See KROK 2013, Round 1, Problem D.
	 */
	static class DisjointUnionSet implements Cloneable{
		
		int[] rank;
		int[] parent;
		
		protected DisjointUnionSet clone(){
			DisjointUnionSet cloned = new DisjointUnionSet(parent.length);
			for(int i=0; i<parent.length; i++){
				cloned.parent[i] = parent[i];
				cloned.rank[i] = rank[i];
			}
			return cloned;
		}

		public DisjointUnionSet(int n) {
			rank = new int[n];
			parent = new int[n];
			
			for (int i = 0; i < n; i++) {
				parent[i] = i;
			}
		}
		
		@Override
		public String toString() {
			return "disj [parents=" + Arrays.toString(parent) + "]";
		}

		/**
		 * Problem specific or general?
		 * O(N * alpha)
		 * 
		 * @param set2
		 */
		public void union(DisjointUnionSet set2){
			for(int i=0; i<parent.length; i++){
				parent[find(i)] = parent[find(set2.find(i))];
			}
		}
		
		
		/**
		 * @param index1 range 0..n-1
		 * @param index2
		 */
		public void union(int index1, int index2){
			int p1 = find(index1);
			int p2 = find(index2);
			
			if (rank[p1] > rank[p2]){
				parent[p2] = p1;
			}else if (rank[p2] > rank[p1]){
				parent[p1] = p2;
			}else{
				parent[p2] = p1;
				rank[p1]++;
			}
		}

		/**
		 *  O(alpha(n)) 
		 * 
		 * @param index
		 * @return
		 */
		private int find(int index) {
			if (parent[index] != index)
				parent[index] =  find(parent[index]);
			return parent[index];
		}
		
		/**
		 * O(N alpha(N)) ==> see find()
		 * 
		 * @return
		 */
		public int getCountDisjointSets(){
			int[] used = new int[parent.length];
			for(int i=0; i<parent.length; i++){
				used[find(i)] = 1;
			}
			int res = 0;
			for(int i=0; i<parent.length; i++){
				res += used[i];
			}
			return res;
		}
	}

	private static Random rnd = new Random();
	public static class ArrayUtils{
		public static void shuffle(int[] a){
			for(int j=a.length-1; j>=1; j--){
				int i = rnd.nextInt(j+1);
				swap(a, i, j);
			}
		}
		
		public static void swap(int[] a, int i, int j){
			int tmp = a[i];
			a[i] = a[j];
			a[j] = tmp;
		}
	}
	
	public static void main(String[] args) {
		new Codeforces_R_200_Div_1_B().run();
	}
	
}