1. The problem is to decode a binary message by reading it 4 bits at a time and replacing each 4-bit code with the corresponding letter from 'a' to 'p'. 2. Each 4-bit binary number corresponds to a letter: 0000 = a, 0001 = b, 0010 = c, ..., 1111 = p. 3. To decode, split the binary string into groups of 4 bits. 4. For each group, convert the 4-bit binary to its decimal equivalent. 5. Map the decimal number to the letter by adding it to the ASCII code of 'a' (which is 97), i.e., letter = chr(97 + decimal). 6. Replace each 4-bit group with its corresponding letter. 7. Continue until the entire binary message is decoded. Final answer: The decoded message is the sequence of letters obtained by converting each 4-bit binary group to its corresponding letter from 'a' to 'p'.