Encoded String

An encoder encodes the **first $16$ lowercase English letters** using $4$ bits each. The first bit (from the left) of the code is $0$ if the letter lies among the first $8$ letters, else it is $1$, signifying that it lies among the last $8$ letters. The second bit of the code is $0$ if the letter lies among the first $4$ letters of those $8$ letters found in the previous step, else it's $1$, signi