import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        char[] chars = sc.next().toCharArray();

        for (int i = 0; i < chars.length; i++) {
            if(i % 2 == 0) {
                if(chars[i] == ' ') {
                    System.out.println("No");
                    return;
                }
            }else {
                if(chars[i] != ' ') {
                    System.out.println("No");
                    return;
                }
            }
        }
        System.out.println("Yes");
    }
}