#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm> 
#include<string>
#include<cstring>
using namespace std;
int main()
{   
    string arr;
    while (cin >> arr) {
        sort(arr.begin(), arr.end());
        cout << arr << endl;
    }
    
    return 0;
}