It is a difficult job to schedule all of the courses in a university to satisfy students' choices with a minimum of conflicts. The task is made all the more difficult when some students don't pre-enroll, or pre-enroll multiple times because they forget that they already did it.
For each requested course, output a line containing the course, a space, and the number of students who requested the course. Output the courses sorted in lexicographical order (with digits sorted before letters).