const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    while(line = await readline()){
       const arr = line.split("");
       const res = arr.sort((a,b) => a.charCodeAt() - b.charCodeAt())
        console.log(res.join(""));
    }
}()