const input = require('fs').readFileSync('/dev/stdin', 'utf8');
const lines = input.trim().split('\n');

while (line = lines.shift()) {
    const numbers = line.split(' ').map(Number);

    // Edit from here
    let a = numbers[0];
    let b = numbers[1];

    if ( a === 0 && b === 0 ) { break; }

    if ( a > b ) {
        const tmp = a;
        a = b;
        b = tmp;
    } 

    const output = a + ' ' + b;
    // to here
    
    console.log(output);
    
}
