I'm currently trying to compute the data (M) bits and check (K) bits of a binary file (transmitfile.bin). I need help as to how to compute and solve for data (m) bits and check (k) bits. To start, would m = 21 since that's the total number of bytes read? I went ahead and computed this assuming m = 21 and I got k = 5, which is correct according to the example output in the picture below but now I'm confused as to how m = 16 in the example since it was 21 to begin with. Did they subtract k (5) from the initial m (21) to get 16 bits? Any explanation would be helpful.  

Assume that the transmitted file contains the following data using the SEC correction code: 111011001011011001100 Transmitted file read The program should read in the transmitted file data and display the following in the console as given below. Transmitted file content: 111011001011011001100 Total number of bytes read: 21 bytes Calculate the data (M) and check (K) bits The program should compute the M and K bits from the data using the following equation: 2K1M+K This is then displayed as the following: M data bits is: 16 K check bits is: 5