题解 | #字符统计#

str_in = input()
#去重
unique_str_in = list(set(str_in))
#获取去重后的ascii码，并根据ascii码升序排序
ascii_str_in = sorted([ord(i) for i in unique_str_in])
#对不同字符计数
count_str_in = [str_in.count(chr(i)) for i in ascii_str_in]
#将计数列表与字符列表合并
count_ascii_str_in = zip(count_str_in,ascii_str_in)
#计数降序优先，ascii码升序次之
def mycmp(str_in):
    return (-str_in[0],str_in[1])
count_ascii_str_in = sorted(count_ascii_str_in,key = mycmp)

for i in count_ascii_str_in:
    print(chr(i[1]),end='')