dictionary = {} while True: line = input() if line == "end": break line_split = line.split(" : ") course_name = line_split[0] student_name = line_split[1] if course_name not in dictionary: dictionary[course_name] = [] dictionary[course_name].append(student_name) for course_name, students in dictionary.items(): print(f"{course_name}: {len(students)}") for student in students: print(f"-- {student}")