Regular Expression

Question

I have value in the following format:

 

144556-1/5/256

 

Before dash the value must be one digit or maximum six digits. After dash the value is acceptabl from 0 to 256. if it contain one digit then it shoud display like this:

 

144556-1

 

If after dash the value contain two digits then it will be separated by slash and should display like this:

 

144556-1/5

 

If after dash the value is three digits then it shoud display like this:

 

144556-1/5/2

 

Please help me how to write Regular Expression for this. Thanks