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'.

Example Input: Question: To calculate the number of different genotypes in any allelic series the formula is applied:
Options: <1> (n-1) / 2. <2> n x (n + 1) / 2. <3> n x (n-1) / 2. <4> (n-1) x (n + 1) / 2. <5> (2n-1) / 2.
Example Output: 2

Example Input: Question: Esters can be obtained from carboxylic acids and alcohols, by applying the Fischer esterification reaction in which:
Options: <1> A base is used as a catalyst. <2> A ketone is used as the solvent. <3> A reducing reagent is used. <4> An oxidizing agent is used. <5> Acid catalysis is used.
Example Output: 5

Example 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.
Example Output:
1