courses of Yordanov

courses = {}
while True:
    txt = input()
    if txt == 'end':
        break
    txt = txt.split(' : ')
    if txt[0] not in courses.keys():
        courses.update({txt[0]: [1, [txt[1]]]})
    else:
        l = []
        l.append(txt[1])
        courses.update({txt[0]: [courses[txt[0]][0] + 1, courses[txt[0]][1] + l]})

for k, v in sorted(courses.items(), key=lambda i: -(i[1][0])):
    print(f'{k}: {v[0]}')
    for i in sorted(v[1], reverse=False):
        print(f'-- {i}')