import java.util.*;
class Main {
  static Scanner sc = new Scanner(System.in);
  public static void main(String[] args) {
    int A=sc.nextInt(),B=sc.nextInt();
    for(int i=1;i<=3;i++){
      if(i!=A&&i!=B){
        System.out.println(i);
        break;
      }
    }
  }
}
/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