'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');