There are 26 letters in the alphabet, ABCDEFGHIJKLMNOPQRSTUVWXYZ
There are 10 digits, 0,1,2,3,4,5,6,7,8,9
Choose the 1st thing, a letter, 26 ways.
Choose the 2nd thing, a letter, 26 ways.
Choose the 3rd thing, a digit, 10 ways.
Choose the 4th thing, a digit, 10 ways.
Choose the 5th thing, a digit, 10 ways.
Choose the 6th thing, a digit, 10 ways.
Choose the 7th thing, a letter, 26 ways.
Choose the 8th thing, a letter, 26 ways.
26•26•10•10•10•10•26•26 = 4569760000
Edwin