import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args)throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		int count = 0;

		while(count < 3000){
			String str = br.readLine();
			String[] s = str.split(" ");

			int a = Integer.parseInt(s[0]);
			int b = Integer.parseInt(s[1]);

			if((0 <= a) && (b <= 10000)){
				if((a == 0)&&(b == 0)){
					break;
				}else if(a > b){
					System.out.println(b +" "+a);
					count++;
					continue;

				}else{
					System.out.println(a +" "+b);
					count++;
					continue;
				}
			}
		}
	}
}
/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