In a certain code language, '-' represents 'x', '÷' represents '+', '+' represents '÷' and 'x' represents '-'. Find out the answer to the following question.
In a row, there are 12 professors between Akash and Bhumi and Akash being the first professor in the row. There are 6 professors between Bhumi and Charu. If there are 15 professors after Charu, then how many minimum professors are there in the row?