'use strict';
process.stdin.on('data', function(chunk) {
    var inputs = chunk.toString().trim().split('\n');
    for (var i = 0; i < inputs.length; i++) {
        if (inputs[i] === '0 0') {
            break;
        }
        var input = inputs[i].split(' ').map(Number).sort(function(a, b) {
            return a - b;
        }).join(' ');
        console.log(input);
    }
});
process.stdin.resume();
process.stdin.setEncoding('utf8');