def integer_to_roman_conversion(x):
    d = {1000:'M',  900:'CM', 500:'D', 400:'CD',100:'C', 90:'XC',50:'L',40:'XL',10:'X',9:'IX',5:'V',4:'IV',1:'I'}
    resp = ''
    while x>0:
        for i in d:
            if i<=x:
                resp+=d[i]
                x=x-i
                break
    return resp


try:
    num = int(input("Enter a positive number between 0 and 1000 : "))
    while True:
        if num>0 and num<1000:
            break
        else:
            num = int(input("Enter a positive number between 0 and 1000 : "))
    print(integer_to_roman_conversion(num))

except ValueError:
    print("The input must be a number.")