题解 | #删除字符串中出现次数最少的字符#

ent = list(input().lower())
ent_set = set(ent)
out_dic = {}

for i in ent_set:
    cou = ent.count(i)
    out_dic.setdefault(cou,[])
    out_dic[cou].append(i)

del_min = out_dic[min(out_dic)]
for i in del_min:
    for j in range(min(out_dic)):
        ent.remove(i)
for i in ent:
    print(i,end='')