import java.util.*;
class Main{
    Scanner sc=new Scanner(System.in);
    void main(){
	while(true){
	    int x=sc.nextInt();
	    int y=sc.nextInt();
	    if(x==0&&y==0)break;
	    if(x<y)System.out.println(x+" "+y);
	    else System.out.println(y+" "+x);
	}
    }
    public static void main(String[]ag){
	new Main().main();
    }
}
/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