#include <sstream>

class Student {
    private:
        int age;
        string first_name;
        string last_name;
        int standard;
        
    public:
        void set_age(int age) {
            this->age = age;
        }
        int get_age() {
            return age;
        }
        
        void set_first_name(string first_name) {
            this->first_name = first_name;
        }
        string get_first_name() {
            return first_name;
        }
        
        void set_last_name(string last_name) {
            this->last_name = last_name;
        }
        string get_last_name() {
            return last_name;
        }
        
        void set_standard(int standard) {
            this->standard = standard;
        }
        int get_standard() {
            return standard;
        }
        
        string to_string() {
            ostringstream oss;
            oss << age << ',' << first_name << ',' << last_name << ',' << standard;
            return oss.str();
        }
};