#include<stdcpp.h>
using namespace std;
class Solution{
public:
    string largestOddNumber(string num){
        string rlt = "";
        for(int i = num.size() - 1 ; i >= 0 ; i--){
            if(num[i]=='1' || num[i] == '3' || num[i] == '5' || num[i] == '7' || num[i] == '9'){
                rlt = num.substr(0,i+1);
                break;
            }
        }
        return rlt;
    }
};
int main(){
    Solution sol;
    cout<<sol.largestOddNumber("52")<<endl;
    cout<<sol.largestOddNumber("2480")<<endl;
    cout<<sol.largestOddNumber("35247")<<endl;
    return 0; 
}