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class Foo {

    private final Lock lock = new ReentrantLock();
    private final Condition condition2 = lock.newCondition();
    private final Condition condition3 = lock.newCondition();

    private boolean isFirstPrinted = false;
    private boolean isSecondPrinted = false;

    public Foo() {
    }

    public void first(Runnable printFirst) throws InterruptedException {
        lock.lock();
        try {
            // printFirst.run() outputs "first". Do not change or remove this line.
            printFirst.run();
            isFirstPrinted = true;
            condition2.signalAll();
        } finally {
            lock.unlock();
        }
    }

    public void second(Runnable printSecond) throws InterruptedException {
        lock.lock();
        try {
            while (!isFirstPrinted) {
                condition2.await();
            }
            // printSecond.run() outputs "second". Do not change or remove this line.
            printSecond.run();
            isSecondPrinted = true;
            condition3.signalAll();
        } finally {
            lock.unlock();
        }
    }

    public void third(Runnable printThird) throws InterruptedException {
        lock.lock();
        try {
            while (!isSecondPrinted) {
                condition3.await();
            }
            // printThird.run() outputs "third". Do not change or remove this line.
            printThird.run();
        } finally {
            lock.unlock();
        }
    }
}