def max(a, b):
    if a > b:
        return a
    else:
        return b

numbers = input(':').split()

system_digits = ['0','1','2','3','4','5','6','7','8','9']
system_letters = ['A','B','C','D','E','F']
list_of_digits = []

letter_check = False
unknown_system = False

for number in numbers:
    for symbol in number:
        list_of_digits.append(symbol)

unknown_system_check = list(set(list_of_digits) - set(system_digits + system_letters))

for number in numbers:
    if number[0] == '0':
        print('Неизвестная система счисления.')
        unknown_system = True
        break
    else:
        for symbol in list_of_digits:
            for system_digit in system_digits:
                bigger_number = 0
                if symbol == system_digit:
                    bigger_number = symbol
                    max_number = max(int(symbol), int(bigger_number))
                else:
                    for system_letter in system_letters:
                        if symbol == system_letter:
                            letter_check = True

if unknown_system:
    pass
else:
    if unknown_system_check != []:
        print('Неизвестная система счисления.')
    else:
        if max_number < 2 and letter_check == 0:
            print('Двоичная система счисления.')
        elif max_number < 8 and letter_check == 0:
            print('Восьмеричная система счисления.')
        elif max_number < 10 and letter_check == 0:
            print('Десятичная система счисления.')
        elif letter_check:
            print('Шестнадцатиричная система счисления.')