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: The mechanism of a homogeneous chemical reaction:
Options: <1> It may include reaction intermediates that are not any of the reactants or any of the products. <2> It is completely defined by the chemical reaction as long as it reflects the correct stoichiometry of the reaction. <3> It is only defined for complex reactions in which the reactants go through many stages before becoming products. <4> It is totally independent of the law of reaction speed. <5> It does not depend on the temperature and is unique for the reaction between certain reagents.
Output:
1