Please solve the programming task below using a self-contained code snippet in a markdown code block.

Your car starts at position 0 and speed +1 on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a sequence of instructions 'A' (accelerate) and 'R' (reverse):

When you get an instruction 'A', your car does the following:

	
position += speed
speed *= 2


When you get an instruction 'R', your car does the following:
	
If your speed is positive then speed = -1
otherwise speed = 1

	Your position stays the same.

For example, after commands "AAR", your car goes to positions 0 --> 1 --> 3 --> 3, and your speed goes to 1 --> 2 --> 4 --> -1.
Given a target position target, return the length of the shortest sequence of instructions to get there.
 
Please complete the following python code precisely:
```python
class Solution:
    def racecar(self, target: int) -> int:
```