familia = ['Антонов','Ефимова','Гордиевских','Девятова']
mark = [5,5,5,5]
familia2 = ['Ефимова','Гордиевских','Девятова','Антонов']
mark_winter = [5,5,5,5]
inpt = input("Введите фамилию студента:")
for curent in familia:
    for crnnt in familia2:
        if(crnnt == inpt and curent == inpt):
            indx = familia.index(crnnt)
            indx2 = familia2.index(crnnt)
            print((mark[indx]+mark_winter[indx2])/2)
            break