You will be given a definition of a task first, then some input of the task.
In this task, you need to provide the correct option for a given problem from the provided options.

Problem: in a class of 52 students , 12 enrolled for both english and german . 22 enrolled for german . if the students of the class enrolled for at least one of the two subjects , then how many students enrolled for only english and not german ? 
Options: a ) 30 , b ) 10 , c ) 18 , d ) 28 , e ) 32
Output:
a