class BiggestNum:
    def __init__(self, number: str):

        self.number = number
        self.bigger_num = []
        self.number_list = []

    def get_bigger(self):
        self.number_list = [x for x in self.number]
        self.bigger_num = [int(i) for i in self.number_list]
        self.bigger_num.sort()
        self.bigger_num.reverse()

    def __repr__(self):
        string_list = list(map(str, self.bigger_num))
        result = f"{''.join(string_list)}"
        return result


big = BiggestNum(number=input())
big.get_bigger()
print(big)