ZFTSH Numeral Systems 4

def arabic_to_roman(res):
    ans = ''
    match res//1000:
        case 3: ans += 'MMM'
        case 2: ans += 'MM'
        case 1: ans += 'M'

    match res//100%10:
        case 9: ans += 'CM'
        case 8: ans += 'DCCC'
        case 7: ans += 'DCC'
        case 6: ans += 'DC'
        case 5: ans += 'D'
        case 4: ans += 'CD'
        case 3: ans += 'CCC'
        case 2: ans += 'CC'
        case 1: ans += 'C'

    match res//10%10:
        case 9: ans += 'XC'
        case 8: ans += 'LXXX'
        case 7: ans += 'LXX'
        case 6: ans += 'LX'
        case 5: ans += 'X'
        case 4: ans += 'XL'
        case 3: ans += 'XXX'
        case 2: ans += 'XX'
        case 1: ans += 'X'

    match res%10:
        case 9: ans += 'IX'
        case 8: ans += 'VIII'
        case 7: ans += 'VII'
        case 6: ans += 'VI'
        case 5: ans += 'V'
        case 4: ans += 'IV'
        case 3: ans += 'III'
        case 2: ans += 'II'
        case 1: ans += 'I'
    return ans

s = input()
res = 0
char_0 = ord('0')
char_9 = ord('9')
is_number = True
end_with_dot = False

for i in range(len(s)):
    if s[i] == '.':
        end_with_dot = True
        break
    elif char_0 <= ord(s[i]) <= char_9:
        res = res*10 + int(s[i])
    else:
        is_number = False
        break

if s[-1] == '.': end_with_dot = True
if not end_with_dot:
    print('Нет точки в конце последовательности!')
elif not is_number:
    print('Это не число!')
else:
    if 0 < res < 4000:
        ans = arabic_to_roman(res)
        print(ans)
    else:
        print('Число должно быть больше 0 и меньше 4000!')