#include    <fstream>
#include    <iostream>
#include    <algorithm>
#include    <cstring>

using namespace std;

ifstream fin("ordine.in");
ofstream fout("ordine.out");

char word[1000005];
int L;

void sort2()
{
    for(int i = 0; i < L; i++)
    {
        cout << word[i];
    }
}

void read()
{
    fin >> word; L = strlen(word);
    sort(word, word + L);
    //sort2();
    fout << word;
}

int main()
{
    read();
    return 0;
}