Triangle $ABC$ has three different integer side lengths. Side $AC$ is the longest side and side $AB$ is the shortest side. If the perimeter of $ABC$ is 384 units, what is the greatest possible difference $AC - AB$?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Triangle $ABC$ has three different integer side lengths. Side $AC$ is the longest side and side $AB$ is the shortest side. If the perimeter of $ABC$ is 384 units, what is the greatest possible difference $AC - AB$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
188\text{ units}
Triangle $ABC$ has three different integer side lengths. Side $AC$ is the longest side and side $AB$ is the shortest side. If the perimeter of $ABC$ is 384 units, what is the greatest possible difference $AC - AB$?
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