public class TwoThreads {
    public static class Thread1 extends Thread {
        public void run() {
            System.out.println("A");
            System.out.println("B");
        }
    }

    public static class Thread2 extends Thread {
        public void run() {
            System.out.println("1");
            System.out.println("2");
        }
    }

    public static class ThreadAB implements Runnable{
        char prv;
        char vtor;
        public ThreadAB(char prv,char vtor){
            this.prv=prv;
            this.vtor=vtor;
        }
        @Override
        public void run() {
              System.out.println(prv);
              System.out.println(vtor);
        }
    }

    public static void main(String[] args) throws InterruptedException {
        Thread t1=new Thread(new ThreadAB('A','B'));
        Thread t2=new Thread(new ThreadAB('1','2'));
        t1.start();
        t1.join();
        t2.start();
        t2.join();

    }

}