import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

	    Scanner scan = new Scanner(System.in);


	    for(;;){
		    int str1 = Integer.parseInt(scan.next());
		    int str2 = Integer.parseInt(scan.next());

	    	if(str1 == 0 && str2 == 0){
	    		break;
	    	}else if(str1 <= str2){
	    	    System.out.println(str1 +" "+ str2);
	    	}else{
	    	    System.out.println(str2 +" "+ str1);
	    	}
	    }

	}
}
/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