'use strict';
process.stdin.on('data', function(chunk) {
  var inputs = chunk.toString();
 for (var i = 0; i < inputs.length; i++) {
 if ( inputs[i] === '0 0') {
 	break;
 }
 var input = input[i].split(' ')
 .map(Number).sort(function(a,b) {
 	return a - b;
 })
 .join(' ');

 console.log(input);
 }

});
process.stdin.resume();
process.stdin.setEncoding('utf8');