def cracks (dmarks, tsubj, namef):
    with open (namef, 'w') as f:
        for stud in dmarks:
            average_mark = dmarks[stud][5]
            if average_mark >=9:
                f.write ('The average mark of ' + stud + ' is ' + str(average_mark) + '\n')
            for i in range(len(dmarks[stud])-1):
                mark =dmarks[stud][i]
                if mark >= 9:
                    f.write ('The mark of ' + stud + ' in ' + tsubj[i] + ' is ' + str(mark) + '\n')