题解 | #字符统计#

input = input()
times = {}
for item in input:
    times[item] = input.count(item)
itemlist = []
for key,item in times.items():
    itemlist.append({'char':key,'count':item})
for i in range(len(itemlist)-1):
    for j in range(i+1, len(itemlist)):
        if itemlist[i]['count'] < itemlist[j]['count'] :
            itemlist[i],itemlist[j] = itemlist[j],itemlist[i]
        elif itemlist[i]['count'] == itemlist[j]['count']:
            if ord(itemlist[i]['char']) > ord(itemlist[j]['char']):
                itemlist[j],itemlist[i] = itemlist[i],itemlist[j]
print(''.join([item['char'] for item in itemlist]))