import java.util.*;

public class Main {
	public Main(int opt1, int opt2) {
		Map<Integer, Integer> map = new HashMap<>();
		map.put(1, 1);
		map.put(2, 2);
		map.put(3, 3);
		map.remove(opt1);
		map.remove(opt2);
		System.out.println(map.entrySet().iterator().next().getValue());

	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int opt1 = sc.nextInt();
		int opt2 = sc.nextInt();
		Main m = new Main(opt1, opt2);

	}
	
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz