import java.util.Scanner;
import java.lang.Math;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class No908 {
  public static void main(String[] args) throws IOException{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String inputValue = br.readLine();
    char[] target = new char[inputValue.length()];

    boolean strFlag = true;
    int comparisonCode = (int)' ';

    for(int i=0;i < inputValue.length();i++){
      target[i] = inputValue.charAt(i);
      int charCode = (int)target[i];
      if((i+1) % 2 == 0 && charCode != comparisonCode
         || (i+1) % 2 != 0 && charCode == comparisonCode){
          strFlag = false;
          break;
      }
    }
      System.out.println(strFlag ? "Yes":"No");
  }
}