Given the following sentence, identify the compound adjective. Output the compound adjective.
The owner drove an old, rusty car.
The compound adjective in the given sentence is "old, rusty".
Complete the following task based on the instruction and optional input provided.### Instruction:
Given the following sentence, identify the compound adjective. Output the compound adjective.

### Input:
The owner drove an old, rusty car.

### Output:
The compound adjective in the given sentence is "old, rusty".