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class Solution:    def romanToInt(self, s: str) -> int:        dic = {   "#":-1, 'I':1, 'V':5, "X":10, "L":50, "C":100, "D":500, "M":1000}        s = s + "#"        ans = 0        pre = s[0]        i = 1        while i < len(s):            if dic[pre] < dic[s[i]]:                ans = ans + dic[s[i]] - dic[pre]                pre = s[i+1]                i = i + 2            else:                ans = ans + dic[pre]                pre = s[i]                i = i + 1        return ans