Kattis

# Course Scheduling

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.

## Input

The first line of input contains an integer $0 \le n \le 100\, 000$, the number of student course requests. Each of the next $n$ lines contains three strings separated by spaces: a student’s first and last name, and the course that the student wishes to take. You may assume that each name is a string of at least one and at most $20$ upper-case letters, and that a course is a string of at least one and at most $10$ upper-case letters and digits. If a student requests a given course more than once, only the first such request should be considered. You may assume that no two students have both their first and last names the same.

## Output

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).

Sample Input 1 Sample Output 1
4
PINK TIE CS241
JOHN DOE CS241
JOHN DOE CSS
JOHN DOE CSS

CS241 2
CSS 1