class Solution {
public:
    int secondHighest(string s) {
        int first = -1;
        int second = -1;
        for(auto ch : s)
        {
            if(isdigit(ch))
            {
                int num = ch - '0';
                if(num > first)
                {
                    second = first;
                    first = num;
                }
                else if(num < first && num > second)
                {
                    second = num;
                }
            }
        }

       
        return second;
    }
};