Uva10469.java

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/**
 *
 * @author mostafa
 */

import java.io.* ;
import java.util.* ;

public class Uva10469 {
    
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader( new InputStreamReader(System.in) );
        PrintWriter pr = new PrintWriter( System.out );
        String s ;
        while( (s = br.readLine()) != null && ! s.isEmpty() )
        {
            StringTokenizer st = new StringTokenizer(s);
            pr.println( Integer.parseInt(st.nextToken()) ^ Integer.parseInt(st.nextToken()) );
        }
        
        br.close();
        pr.close();
    }
    
}