import java.util.Scanner;

public class No69 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String A = sc.next();
		String B = sc.next();
		char a [] = new char[A.length()];
		char b [] = new char[B.length()];
		char x;
		
		for(int i = 0;i < a.length;i++) {
			a[i] = A.charAt(i);
			b[i] = B.charAt(i);
		}
		
		for(int i = 0;i < a.length;i++) {
			for(int j = i + 1;j < a.length;j++) {
				if(a[i] > a[j]) {
					x = a[i];
					a[i] = a[j];
					a[j] = x;
				}
				if(b[i] > b[j]) {
					x = b[i];
					b[i] = b[j];
					b[j] = x;
				}
			}
		}
		
		for(int i = 0;i < a.length;i++) {
			if(a[i] != b[i]) {
				System.out.println("NO");
				break;
			}
			if(i == a.length - 1) {
				System.out.println("YES");
			}
		}
	}
}