def reverse_roman(roman_string):
    mille = ['', 'M', 'MM', 'MMM']
    centaine = ['', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM']
    dixaine = ['', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC']
    unite = ['', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX']
    number = 0
    roman_string_length = len(roman_string)
    index = 0
    while True:
        letter = roman_string[index]
        current_number = letter
        is_multiple = False
        if current_number in mille:
            while current_number in mille and index < roman_string_length - 1:
                index += 1
                current_number += roman_string[index]
            if current_number not in mille:
                is_multiple = True
                current_number = current_number[0:-1]
            number += (mille.index(current_number) * 1000)
        elif current_number in centaine:
            while current_number in centaine and index < roman_string_length - 1:
                index += 1
                current_number += roman_string[index]
            if current_number not in centaine:
                is_multiple = True
                current_number = current_number[0:-1]
            number += 100 * (centaine.index(current_number))
        elif current_number in dixaine:
            while current_number in dixaine and index < roman_string_length - 1:
                index += 1
                current_number += roman_string[index]
            if current_number not in dixaine:
                is_multiple = True
                current_number = current_number[0:-1]
            number += 10 * (dixaine.index(current_number))
        elif current_number in unite:
            while current_number in unite and index < roman_string_length - 1:
                index += 1
                current_number += roman_string[index]
            if current_number not in unite:
                is_multiple = True
                current_number = current_number[0:-1]
            number += unite.index(current_number)

        if index == roman_string_length - 1:
            if is_multiple:
                letter = roman_string[index]
                if letter in mille:
                    number += (mille.index(letter)) * 1000
                elif letter in centaine:
                    number += 100 * (centaine.index(letter))
                elif letter in dixaine:
                    number += 10 * (dixaine.index(letter))
                elif letter in unite:
                    number += unite.index(letter)
            break

    return number


if __name__ == '__main__':
    # These "asserts" using only for self-checking and not necessary for auto-testing
    assert reverse_roman('VI') == 6, '6'
    assert reverse_roman('LXXVI') == 76, '76'
    assert reverse_roman('CDXCIX') == 499, '499'
    assert reverse_roman('MMMDCCCLXXXVIII') == 3888, '3888'
    assert reverse_roman("I") == 1, '1'
    assert reverse_roman("X") == 10, '10'
    assert reverse_roman("MMMDCCCX") == 3810, '3810'
    print('Great! It is time to Check your code!')