import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.ArrayDeque;
import java.util.Queue;
import java.util.HashSet;
import java.io.*;

public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long a = fs.nextLong();
        long b = fs.nextLong();
        long x = 0;
        long y = 0;
      	long d = 0;
      	if((a-1) % 2 == 0){
          d = (a-1)/2;
          if(d % 2 == 0){
            x = 0^(a-1); 
          }
          else{
            x = 1^(a-1);
          }
        }
        else{
          d = (a+1)/2;
          if(d%2 == 0){
            x = 0;
          }
          else{
            x = 1;
          }
        }
        
        if(b % 2 == 0){
          d = b/2;
          if(d % 2 == 0){
            y = 0^b; 
          }
          else{
            y = 1^b;
          }
        }
        
        else{
          d = (b+1)/2;
          if(d%2 == 0){
            y = 0;
          }
          else{
            y = 1;
          }
        }
        System.out.println(x^y);

}
  public static int calcMin(int[] array) {

    int intMin = array[0];

    for (int i = 1; i < array.length; i++ ) {
        if(intMin > array[i]) {
            intMin = array[i];
        }
    }
    return intMin;
}
}
class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte(){
        if(ptr < buflen){
            return true;
        }else{
            ptr = 0;
            try{
                buflen = in.read(buffer);
            }catch(IOException e){
                e.printStackTrace();
            }
            if(buflen <=0){
                return false;
            }
        }
        return true;
    }

    private int readByte(){
        if(hasNextByte())return buffer[ptr++];
        else return -1;
    }

    private static boolean isPrintableChar(int c){
        return 33<=c && c<=126;
    }
    public boolean hasNext(){
        while(hasNextByte() && !isPrintableChar(buffer[ptr]))ptr++;
        return hasNextByte();
    }

    public String next(){
        if(!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)){
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    public long nextLong(){
        if(!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if(b == '-'){
            minus = true;
            b = readByte();
        }
        if(b < '0' || '9' < b){
            throw new NumberFormatException();
        }
        while(true){
            if('0' <= b && b<='9'){
                n*=10;
                n+=b-'0';
            }else if(b==-1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt(){
        long nl = nextLong();
        if(nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDoutble(){return Double.parseDouble(next());}
}


Measured memory_bytes: 23252