#include <iostream>
#include <string.h>
#include <algorithm>

using namespace std;

int main() {
    char s[32];
    while (scanf("%s", &s) != EOF) {
        int len = strlen(s);
        sort(s, s + len);
        for (int i = 0; i < len; i++)
            printf("%c", s[i]);
        printf("\n");
    }
    return 0;
}