#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;
}