 A second example of arranging distinct objects into sequences is sometimes seen in classical encryption ciphers which use, for example, the English text as input. If we have our 26 English characters, English letters, considering just the uppercase letter, ignoring lowercase, then how many possible arrangements can we have of those letters? Then we can, of course, in alphabetical order, a, b, c, d, all the way through to z, but we can try different arrangements which are not in alphabetical order. For example, we could have b, a, c, d, e, through to z, and other arrangements. And the total number of possible arrangements that we can have is 26 factorial, which is approximately 4 by 10 to the power of 26.