import random
marks = []
for i in range (1,11):
     marks.append (random.randint(2,5))
print (marks, end=' ')
summ=0
for i in range (1, len(marks)):
    if marks [i] == 2 and i == len(marks) :
        summ += marks[i]
    elif marks[i]== 2 and i != len(marks):
        if marks [i+1] == 2:
            summ += 0
        elif marks[i+1] != 2:
            summ+= marks [i]
    else:
        summ+= marks[i]
print ()
print (int (summ // len(marks)))

 if marks [i+1] == 2:

 >>> a = [5, 3, 2, 2, 2, 3, 5, 2, 3, 3]
>>> len(a)
10
>>> a [10]
Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    a [10]
IndexError: list index out of range
>>>

 elif marks[i]== 2 and i != len(marks):

 if marks [i+1] == 2:

 if marks[I] == 2 and i < (Len(marks) -1 )

 and i < (Len(marks))