#include <stdio.h>
#include <string.h>
#include <stdbool.h>

int main() {
    char inputString[100] = {0};
    int length = 0, i = 0;
    bool moved = true;
    char temp;
    scanf("%s", inputString);
    length = strlen(inputString);
    while (moved) {
        moved = false;
        for (int i = 0; i < length-1; i++) {
            if (inputString[i] < inputString[i+1]) {
                temp = inputString[i];
                inputString[i] = inputString[i+1];
                inputString[i+1] = temp;
                moved = true;
            }
        }
    }
    printf("%s\n", inputString);
    return 0;
}