def checkio(data):
    result=""
    NUMERALS=(('M',1000),('CM',900),('D',500),('CD',400),('C',100),('XC',90),
              ('L',50),('XL',40),('X',10),('IX',9),('V',5),('IV',4),('I',1))
    for numeral, number in NUMERALS:
        while number<=data:
            data-=number
            result+=numeral
    return result