罗马数字转换

class Solution(object):    
    def romanToInt(self, s):
        sum=0        
        convert={'M': 1000,'D': 500 ,'C': 100,'L': 50,'X': 10,'V': 5,'I': 1} 
        for i in range(len(s)-1):            
            if convert[s[i]] < convert[s[i+1]]:
                sum -= convert[s[i]]            
            else:                
                sum += convert[s[i]]        
        sum += convert[s[-1]]        
        return sum
if __name__ == '__main__':
    a = Solution()
    n=list(input())
    palindrome_bool = a.romanToInt(n)
    print(palindrome_bool)