题解

while True:
    try:
        data = input()
        record = [0 for _ in range(62)]
        for x in data:
            if 'A' <= x <= 'Z':
                record[ord(x) - ord('A') + 10] += 1
            elif 'a' <= x <= 'z':
                record[ord(x) - ord('a') + 36] += 1
            else:
                record[ord(x) - ord('0')] += 1
        ret = ""
        for i in range(0, len(record)):
            if i < 10:
                ret += record[i] * chr(ord('0') + i)
            elif i < 36:
                ret += record[i] * chr(ord('A') + i - 10)
            else:
                ret += record[i] * chr(ord('a') + i - 36)
        print(ret)
    except:
        break