course_bruteforce

import string

first = [i for i in range(7)]
second = ["{}{}".format(a,b) for a in string.ascii_uppercase for b in string.ascii_uppercase]
third = ['{}'.format(i).zfill(3) for i in range(10)]


big_list = []

for a in first:
    for b in second:
        for c in third:
            big_list.append('{}{}{}'.format(a, b, c))

print(len(big_list))