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'.

Ex Input:
Question: The BRCA-1 gene mutation is associated with a high risk of:
Options: <1> Acute myocardial infarction. <2> Breast cancer <3> Alzheimer disease. <4> Parkinson's disease <5> Tay-Sach disease.

Ex Output:
2

Ex Input:
Question: Of the following reaction mechanisms, in which there is an inversion of the configuration from the reactant to the product of the reaction ?:
Options: <1> Bimolecular nucleophilic substitution (SN2). <2> Unimolecular elimination (E1). <3> Unimolecular nucleophilic substitution (SN1). <4> Addition Markovnikov. <5> Addition anti-Markovnikov.

Ex Output:
1

Ex Input:
Question: When an enzyme catalyzes a reaction:
Options: <1> It is not modified and can be reused. <2> It does not change, but it loses its activity. <3> It always requires the participation of cofactors. <4> It denatures to facilitate bonding with the substrate. <5> It always requires energy.

Ex Output:
1