import java.util.Scanner;

public class Main {

	public static void main (String[] args) {

		Scanner sc = new Scanner(System.in);
		
		for (;;) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			if (a == 0 && b == 0) break;
			System.out.println(a < b ? (a + " " + b) : (b + " " + a));
		}
		
		sc.close();
	}

}
/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