#!/usr/bin/python

def romanToInt(s):
    d = {'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M':1000, 'IV':4, \
            'IX':9, 'XL':40, 'XC':90, 'CD':400, 'CM':900}

    n = 0
    i = 0
    while i < len(s)-1:
        if d[s[i]] >= d[s[i+1]]:
            n += d[s[i]]
            i += 1
        else:
            n += d[s[i]+s[i+1]]
            i += 2

    if i < len(s):
        n += d[s[i]]

    return n

if __name__ == '__main__':
    print romanToInt('III')
    print romanToInt('IV')
    print romanToInt('IX')
    print romanToInt('LVIII')
    print romanToInt('MCMXCIV')