as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
generate an algorithm to calculate letter frequency in a given sentence.
user
algorithm:

1. initialize an empty dictionary to store results
2. loop through the given sentence and get each letter
3. if the letter is already in the dictionary, increment the count by 1
4. if the letter is not present in the dictionary, add the letter to the dictionary and set the count to 1
5. repeat steps 2 and 3 till the end of the sentence
6. return the result dictionary
assistant