поправка на задача

name = input()
grades = 1.0
sums = 0.0
expel_counter = 0

while grades <= 12:
    grade = float(input())

    if grade < 4.00:
        expel_counter += 1

    if expel_counter == 2:
        break

    if grade >= 4.00:
        sums += grade
        grades += 1
    average = sums / 12

if expel_counter == 2:
    print(f'{name} has been excluded at {round(grades)} grade')
else:
    print(f'{name} graduated. Average grade: {average:.2f}')