import java.io.*;

public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		while(true){
			String[] str = (br.readLine()).split(" ");
			int x = Integer.parseInt(str[0]); 
			int y = Integer.parseInt(str[1]); 
			if ( x==0 && y==0) {
				break;
			}else if(x < y){
				sb.append(x).append(" ").append(y).append("\n");
			}else{
				sb.append(y).append(" ").append(x).append("\n");
			}
		}
		System.out.print(sb);
	}
}
/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