One more wrinkle to take into account. Previous postings stated "the result is then applied to the alphabet. 0 = A, 1 = B, 2 = C, 3 = D, etc until 23 = X." This is not quite true. I and O (India and Oscar) are omitted from the sequence to avoid confusion so H=7 and J = 8, then N=12 and P = 13, ending up with Z=23 (which is, of course, why 23 is the divisor).