Ciphers in which pairs of numbers replace each letter are called bilateral or dinome ciphers. A simple way to construct such ciphers is to put the letters of the alphabet into a rectangle and number the rows and the columns. For example, if we use a five-by-five square, and squash i and j together, we have 1 a f 1 1 2 3 4 9 5 V 1 2 3 4 T T P I 2 W E U T 3 E U 4 T A 5 S V T J 6 N 7 3 4 5 d ij n 0 r S t W X y Z 2 b g m C h To encipher, replace the letter by its row-column number pair that is, read from the side first. So the word "box" becomes 12 34 53. Deciphering is just translating back into letters. A larger bipartite cipher was used by Brig. General Leslie R. Groves. It took the following form: 5 6 7 OU 0 G N BTN ZMD I e k P u 8 L E A O L NS U CB A F R S 8 T CWY R U AM MV T 9 0 P N O S T OE Y H GO E I R N 9 0 L S R E T D E AH E HP DI XQ (a) Groves used this cipher for certain telephone conversations during the building of the atomic bomb. Encipher the plaintext "atomic bomb". (b) Decipher 01-53 72-29-01 96-22-25-70 45-74 77-47-28-92-42. He was Groves' phone partner. (c) The bomb was developed at 28-92-66 62-01-08-19-15-39. Find this information.