Write the systematic IUPAC names of the following compounds :
`CH_3 - overset(SH) overset(|) CH -CH_2 - underset(CH_2 CH_3 ) underset(|) overset(CH_3 ) overset(|) C- overset(O ) overset(||) C-OH`

Explanation

To derive the systematic IUPAC name of the given compound, we will follow these steps:

### Step 1: Identify the longest carbon chain
The compound has a total of 5 carbon atoms in the longest continuous chain. This chain includes the carboxylic acid functional group (-COOH) and the mercapto group (-SH).

### Step 2: Number the carbon chain
We need to number the carbon chain in such a way that the functional groups receive the lowest possible numbers. The carboxylic acid group has the highest priority, so we will start numbering from the end of the chain nearest to the -COOH group.

...