Give the systematic IUPAC names of the following compounds :
`CH_3 - CH = CHoverset(CH_3) overset(|)CH - CH_3`

Explanation

To determine the systematic IUPAC name of the given compound, follow these steps:

### Step 1: Identify the longest carbon chain
- Look for the longest continuous chain of carbon atoms in the compound. In this case, the longest chain consists of 5 carbon atoms.

### Step 2: Number the carbon chain
- Number the carbon chain in such a way that the double bond receives the lowest possible number. Start numbering from the end closest to the double bond.
- In this case, if we start from the left, the double bond is at carbon 2, which is the lowest possible number.
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