my_top_student={"hassan","imran",'ali','ahmed',"talha"}
print("my top scoring student in programming are :",my_top_student)
print("oh i miss one student let me add his name too")
print("previously i have added :" +str(len(my_top_student))+" student in my list")
my_top_student.add('usama')
print("thanks i have remeber him")
print("now my top studetn names are:",my_top_student)
print("now after adding i have :"+str(len(my_top_student))+"studet in my list")