import java.util.concurrent.*;

public class book {
    Semaphore[] booklock = new Semaphore[1000]; // for every book, initialized to 1

    public void getBooks(long book1, long  book2, long book3) throws InterruptedException{

	int[] mybooks = {(int) book1, (int) book2, (int) book3};

        qsort(mybooks);
        
	if(mybooks[0] !=0)
        booklock[mybooks[0]].acquire();
        if (mybooks[1] !=0)
        booklock[mybooks[1]].acquire();
        if (mybooks[2] !=0)
        booklock[mybooks[2]].acquire();
	}
}