题解 | #删除字符串中出现次数最少的字符#
'''
写复杂了，本质上是用set去重，再用字典记录每个字符的数量，排序后去掉最小的字符，有很多地方还可以优化
'''
x = input()
x_list = list(x)
x_set = set(x_list)
x_dict = {}
for i in x_set:
x_dict[i] = x.count(i)
x_key = dict(sorted(x_dict.items(),key=lambda x:x[1],reverse = False)).keys()
ans_list = []
for key in x_key:
if not ans_list:
ans_list.append(key)
elif x_dict[key]==x_dict[ans_list[-1]]:
ans_list.append(key)
elif x_dict[key] > x_dict[ans_list[-1]]:
break
else:
break
for key in ans_list:
x = x.replace(key,'')
print(x)
