#include <stdio.h>
const int MAX = 1024;
int getIndex(char arr[], int left, int right) {
int pivot = arr[left];
while (left < right) {
// 从右往左
while (left < right && arr[right] >= pivot) right--;
arr[left] = arr[right];
// 从左往右
while (left < right && arr[left] <= pivot) left++;
arr[right] = arr[left];
}
arr[left] = pivot;
return left;
}
void qSort(char arr[], int left, int right) {
if (left < right) {
int index = getIndex(arr, left, right);
qSort(arr, left, index-1);
qSort(arr, index+1, right);
}
}
int main() {
char string[MAX];
while(scanf("%s", string) != -1) {
qSort(string, 0, strlen(string)-1);
printf("%s\n", string);
}
return 0;
}