You will be given a definition of a task first, then some input of the task.
In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: Acute ischemia of a limb consists of a sharp decrease in arterial perfusion. It is important to differentiate between thrombosis and arterial embolism to be able to indicate the most appropriate treatment. Which of the following is correct?
Options: <1> The presence of embolic focus and distal pulses in the contralateral limb leads to the suspicion of arterial thrombosis. <2> If the patient has a history of claudication and the clinic is of sudden onset, we will suspect arterial embolism in the first place. <3> If the contralateral limb has all the pulses present and the clinic starts slowly, we will suspect an arterial thrombosis. <4> If the clinic starts abruptly in a patient with embolism focus, we will suspect arterial embolism. <5> If the patient is a carrier of a previous arterial derivation, we will suspect arterial embolism.
Output:
4