while True:
    try:
        string = input()
        dictionary = {}
        for i in string:
            if i not in dictionary:
                dictionary[i] = 1
            else:
                dictionary[i] += 1
        min_num = sorted(dictionary.values())[0]
        nlist = []
        for i in dictionary.keys():
            if dictionary[i] == min_num:
                nlist.append(i)
        result = ''
        for i in string:
            if i in nlist:
                continue
            else:
                result += i
        print(result)
    except EOFError:
        break