import java.util.Scanner;

public class No3547 {

	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int n = Integer.parseInt(scanner.next());
		int m = Integer.parseInt(scanner.next());
		
		scanner.close();
		
		String nString = Integer.toBinaryString(n);
		String mString = Integer.toBinaryString(m);
		
		int max = Math.max(nString.length(), mString.length());

		nString = "0".repeat(max - nString.length()).concat(nString);
		mString = "0".repeat(max - mString.length()).concat(mString);
		
		System.out.println(nString);
		System.out.println(mString);
		
		String ans = "";
		
		int i = 0;
		for(i = 0;i < max;i++) {
			
			if((max - 1 - i) % 2 == 0) {
				
				if('0' == mString.charAt(i)){
					ans = ans.concat("0");
				}else if('1' == nString.charAt(i)) {
					ans = ans.concat("1");
				}else {
					ans = "-1";
					break;
				}
				
			}else {
				
				if(nString.charAt(i) == mString.charAt(i)) {
					ans = ans.concat("0");
				}else if('0' == nString.charAt(i)) {
					ans = ans.concat("1");
				}else {
					ans = "-1";
					break;
				}
			}
						
		}
		
		if(!"-1".equals(ans)) {
			System.out.println(Integer.parseUnsignedInt(ans, 2));
		}else {
			System.out.println(ans);
		}
		
	}

}