Hint: Steps for developing the program

1. Count the number of a's in the file.
2. After processing that file for a's, add code to count the number of b's.
3. Convert the program to count the number of a given letter inside a loop that goes from 'a' to 'z'. (A for loop can iterate through letters)
4. Write a separate program to count the number of a's in each line.
5. Combine the two programs