题解 | #字符统计#

a=input()
dic={}
ls=[]
for i in range(len(a)):
    if a[i] not in dic:
        dic[a[i]] = 1
    else:
        dic[a[i]]+=1
a=sorted(dic.items(),key=lambda ele:(-ele[1],ele[0]))
for i in range(len(a)):
    ls.append(a[i][0])
print("".join(ls))