import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); int i = 0; for ( ; i < s.length(); i++) { String c = String.valueOf(s.charAt(i)); if (i % 2 == 0) { if (c.equals(" ")) { break; } } if (i % 2 == 1) { if (!(c.equals(" "))) { break; } } } if (i == s.length()) { System.out.println("Yes"); } else { System.out.println("No"); } } }