import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		int N = 3000;
		int x = 0;
		int y = 0;
		Scanner scan = new Scanner(System.in);
		for (int i = 0; i < 3000; i++) {
			x = scan.nextInt();
			y = scan.nextInt();
			if (x != 0 || y != 0) {
				if (x < y) {
					System.out.println(x + " "+ y);
				} else {
					System.out.println(y + " " + x);
				}
			} else
				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