Miss M lives on the planet Bitaqulandia, where the most popular currency is the bitqoin. 
Recently, Miss M held a mini-competition for friends, where each winner receives exactly three bitqoins.

It is known that in Miss M's competition, the prize fund is $n$ bitqoins, $m$ people won, and each winner receives exactly three bitqoins.

Determine how many bitqoins will remain with Miss M if she gives three bitqoins to each winner. It is known that Miss M has enough bitqoins.