package yukiCoder;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class No00069 {

	public static void main(String[] args) {
		BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

		try {
			String input1 = bufferedReader.readLine();
			String input2 = bufferedReader.readLine();

			System.out.println(isEqual(input1, input2) ? "YES" : "NO");

		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public static Boolean isEqual(String input1 , String input2) {
		String[] indexArray = new String[input1.length()];
		for(int i = 0 ; i < input2.length() ; i++) {
			String input2Digit = String.valueOf(input2.charAt(i));
			for(int j = 0 ; j < input1.length() ; j++) {
				String input1Digit = String.valueOf(input1.charAt(j));
				if(indexArray[j] == null && input1Digit.equals(input2Digit)) {
					indexArray[j] = input1Digit;
					break;
				}
			}
		}
		StringBuilder builder = new StringBuilder();
		for (int i = 0 ; i < indexArray.length ; i++) {
			builder.append(indexArray[i]);
		}
		return input1.equals(builder.toString()) ? true : false;
	}
}