A robot is sitting in a chair with its arms facing down.

Write an algorithm, using pseudocode, to make the robot:

1. stand up
2. walk forward until it senses a wall
3. turn around
4. walk back to the chair
5. sit down in its original starting position

Finally, output the total number of steps taken.

Commands
--------
In addition to our standard pseudocode commands, you must also use the following robot control commands:

sit
stand
step (one step forward)
raise arms (parallel to floor)
lower arms (pointing to floor)
sense (only if arms are raised)
turn (90 degrees right)

Immediately after issuing a sense command, you can check whether the robot is at the wall as follows:

if at wall
or alternatively
if not at wall

Assumptions
-----------
You must assume the following facts:

The robot's initial sitting position is directly facing the target wall.
There are no obstacles between