import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        boolean flag = true;
        char temp;
        for(int i = 0; i < str.length(); i++) {
            temp = str.charAt(i);
            if(i % 2 == 0 && temp == ' ') flag = false;
            else if(i % 2 == 1 && temp != ' ') flag = false;
        }
        System.out.println((flag)? "Yes" : "No");
    }
}