public class Test {
	
	public static void main(String[] args) {
		for(int i = 0; i < 49; i++) {
			new Student();
		}
		System.out.println(new Student().getCount());	// 50
		for(int i = 0; i < 49; i++) {
			new Teacher();
		}
		System.out.println(new Student().getCount());	// 100
	}
	
}

abstract class Person {
	
	protected static int count;
	
	public abstract int getCount();
}

class Student extends Person {
	
	public Student() {
		super.count++;
	}
	
	@Override
	public int getCount(){
		
		return super.count;
	}
}

class Teacher extends Person {
	
	public Teacher() {
		super.count++;
	}
	
	@Override
	public int getCount() {
		
		return super.count;
	}
}