Ultrasonic Sensor

[jeeep]

Hello,
I am using an ultrasonic range finder with the following code on my arduino: http://www.arduino.cc/en/Tutorial/UltrasoundSensor

In the serial monitor I am getting readings such as these:
A5905
A31143
A15740
A-11826

What does this mean (minus the "A") and how do I get this into inches?

[mem]

There is code in the playground here: Arduino Playground - UltrasonicSensor that you can use to print the distance in inches. google is your friend