转换成ascil码，排序即可

try:
    while True:
        str1 = str(input())

        num1 = []

        for i in str1:
            num1.append(ord(i))

        num1.sort()

        str2 = ''

        for i in range(len(num1)):
            str2 += chr(num1[i])

        print(str2)

except:
    pass