courses_list = []
for course, mentor, duration in zip(courses, mentors, durations):
    course_dict = {"title": course, "mentors": mentor, "duration": duration}
    courses_list.append(course_dict)

for course in courses_list:
    all_list = []
    for name in course['mentors']:
        all_list.append(name.split(' ')[0])
    unique_names = set(all_list)

    same_name_list = []
    for name in unique_names:
        if all_list.count(name) > 1:

            for mentor in course["mentors"]:
                if name in mentor:
                    same_name_list.append(mentor)
    if len(same_name_list) > 0:

        print(f'На курсе {course["title"]} есть тёзки: {", ".join(sorted(same_name_list))}')