import java.util.*;

class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		
		String[] a = sc.next().split("\\.",0);
		String[] b = sc.next().split("\\.",0);
		String ans = "NO";
		
		
		for (int i=0; i<3; i++) {
			if (b[i].compareTo(a[i]) < 0) {
				ans = "YES"; break;
			}
		}
		System.out.println(ans);
		
	}
}