Revise paste Untitled

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
import java.util.concurrent.Semaphore;

public class Main {
    public static  void main(String[] args) throws InterruptedException{
        Factory f = new Factory(2);
        List<Thread> ls = new ArrayList<>();
        for(int i = 0; i < 3; i++) {
            ls.add(new Thread(new Runnable() {
                @Override
                public void run() {
                    Random rnd = new Random();
                    if(rnd.nextInt() % 2 == 0) {
                        try {
                            f.produce_vaccine(new String("v" + rnd.nextInt() % 10));
                        }
                        catch (InterruptedException ex) {

}
                    }
                    else {
                        try {
                            f.buy_vaccine();
                        }
                        catch (InterruptedException ex) {

}
                    }
                }
            }));
        }
        for(int i = 0; i < 3; i++) {
            ls.get(i).start();
        }
        for(int i  =0; i < 3; i++) {
            try {
                ls.get(i).join();
            }
            catch (InterruptedException ex) {

}
        }

}
}