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class Solution {
public:
    
    int romanToDigit(char s){
        switch(s)
        {
            case 'I':
                return 1;
                break;
            case 'V':
                return 5;
                break;
            case 'X':
                return 10;
                break;
            case 'L':
                return 50;
                break;
            case 'C':
                return 100;
                break;
            case 'D':
                return 500;
                break;
            case 'M':
                return 1000;
                break;
        }
        return 0;
    }
    
    int romanToInt(string s) {
        int store=0;
        int last=0;
        int temp=0;
        for (int i=0;i<s.length();i++)
        {
            temp=romanToDigit(s[i]);
            store=store+temp;
            if (temp>last)
                store=store-2*last;
            last=temp;
        }
        return store;
    }

};