题解 | #删除字符串中出现次数最少的字符#

string = input()
str_list = []
num_list = []

for str1 in string:
    if str1 not in str_list:
        str_list.append(str1)

for str2 in str_list:
    num_list.append(string.count(str2))

index_min = num_list.index(min(num_list))

flag = num_list[index_min]

while min(num_list) == flag:
    index_min = num_list.index(min(num_list))
    min_str = str_list[index_min]
    string = string.replace(min_str, '')
    del num_list[index_min]
    del str_list[index_min]
    

print(string)