Untitled

import java.util.* ;

// task 1 starts
abstract class student{

    abstract void take_exam();
}
class phdStudent extends student{
    void take_exam(){
        System.out.println("PHD student takes FINAL DEFENSE EXAM");
    }
}
class gradStudent extends student{
    void take_exam(){
        System.out.println("Grad student takes WRITTEN PAPER EXAM");
    }
}
// task 1 ends



// task 2 starts




// task 2 ends



public class Main {
    public static void main(String[] args) {

        //task 1
        student st = new phdStudent();
        st.take_exam();
        student st2 = new gradStudent();
        st2.take_exam();

        //task 2
    }
}